The Explanatory Stopgap

Eric Lormand
University of Michigan

Forthcoming 2005 in Philosophical Review

             Is there an explanatory gap between raw feels and raw material?  Some philosophers argue, and many other people believe, that scientific explanations of conscious experience cannot be as satisfying as typical scientific explanations elsewhere, even in our wildest dreams.  The underlying philosophical claims are:

   (i)      typically when satisfactory explanations are available in other domains of science, what is explained is conceptually necessitated by what explains it, although

   (ii)     the existence of conscious experience is not conceptually necessitated by any possible combination of premises about the nonconscious or the nonexperiential. 

This requirement of conceptual (epistemological, a priori) necessitation is, intentionally, demanding in the extreme.  Claim (i) is usually argued for by giving examples from science that seem to fulfill it.  More generally, it seems to be motivated by the idea that explanation answers questions, and that a fully satisfying answer to a question should not raise a new question in its place.  For example, a fully satisfying answer to the question 'what is necessary and sufficient for consciousness [or life, water, rocks, and so on]?' should not in turn raise the question 'why is that necessary and sufficient for consciousness [life, water, rocks]?'  And, it must be admitted, nothing closes off further questions quite like revealing them to presuppose conceptual contradictions.  While I think there is much to be said against this stringent requirement on fully satisfactory explanation--both by arguing against the examples adduced in support of claim (i), and by arguing that questions may be rendered pointless without resting on conceptual contradictions--my aim in this article is to argue against (ii), and indeed to show in detail, step by conceptually necessary step, how to deduce phenomenal feels from purely nonphenomenal material.   

1     The gap

            Since the appearance of Thomas Nagel's "What is it like to be a bat?" defenders of the explanatory gap have been getting bolder with each passing decade.  Nagel claims in that article that there is a "gap between subjective and objective," but he does not wield his bat against the metaphysical doctrine that everything mental is physical.  Rather, he argues that the gap is in our current understanding of this doctrine: "we do not at present have any conception of how it might be true" (1974, 176, my emphasis).  Joseph Levine, the originator of the phrase 'explanatory gap,' concurs that the gap is epistemological rather than metaphysical, but strengthens the epistemological upshot: "there is a significant problem about our ever coming to know that statements like ['pain is the firing of C‑fibers'] are true" (1983, 359, my emphasis).  Most recently, David Chalmers argues from the explanatory gap not only to epistemological conclusions but also to a wide range of squarely metaphysical positions, including property dualism, epiphenomenalism, and even panpsychism (1996; for a more modest panpsychism, see Nagel 1979).  My concern in this article is not with these family squabbles about the ramifications of the gap, but with its alleged source. 

            Fortunately, gap‑theorists speak in unison here; all emphasize that the explanatorily recalcitrant aspect of conscious experiences is that there is something it is like to have them.  Nagel explains the troublesome sense of 'conscious' as follows:

[F]undamentally an organism has conscious mental states if and only if there is something it is like to be that organism--something it is like for the organism.  We may call this the subjective character of experience.  It is not captured by any of the familiar, recently devised reductive analyses of the mental, for all of them are logically compatible with its absence.  (1974, 166)

Levine similarly insists that "what is at issue is the ability to explain qualitative character itself; why it is like what it is like to see red or feel pain" (1993, 128), and maintains: 

No matter how rich the information processing or the neurophysiological story gets, it still seems quite coherent to imagine that all that should be going on without there being anything it's like to undergo the states in question.  (Levine 1993, 129)

Chalmers characterizes the problem most fundamentally in the same 'something it is like' way, then adds more jargon‑laden characterizations:

We can say that a being is conscious if there is something it is like to be that being ....  Similarly, a mental state is conscious if there is something it is like to be in that mental state.  To put it another way, we can say that a mental state is conscious if it has a qualitative feel--an associated quality of experience.  These qualitative feels are also known as phenomenal qualities, or qualia for short.  The problem of explaining these phenomenal qualities is just the problem of explaining consciousness.  This is the really hard part of the mind‑body problem.  (1996, 4)

Why is it so hard, according to Chalmers?   For exactly the reasons specified by Nagel and Levine:

[N]o matter what functional account of cognition one gives, it seems logically possible that that account could be instantiated without any accompanying consciousness.  It may be naturally impossible--consciousness may in fact arise from that functional organization in the actual world--but the important thing is that the notion is logically coherent.  If this is indeed logically possible, then any functional and indeed any physical account of mental phenomena will be fundamentally incomplete.  (1996, 47)

Helpfully, Chalmers hones the challenge as follows:

If proponents of reductive explanation are to have any hope of defeating the arguments above, they will have to give us some idea of how the existence of consciousness might be entailed by physical facts.  While it is not fair to expect all the details, one at least needs an account of how such an entailment might possibly go.  But any attempt to demonstrate such an entailment is doomed to failure.  For consciousness to be entailed by a set of physical facts, one would need some kind of analysis of the notion of consciousness--the kind of analysis whose satisfaction physical states could imply--and there is no such analysis to be had.  (1996, 104)

Okay, then: I choose both "truth" and "dare."  I will try to give defenders of the explanatory gap exactly what they say they want.   

2     The stopgap 

            Clearly, to avoid charges of missing the point, my attempt to stop up the explanatory gap must come face‑to‑face with the concept of there being something it is like for a creature to have a feature.  The feature might be a nonmental kind-property (being a bat, being human, being the creature itself, ...), or a nonmental bodily or environmental property (flying, going to the store, being bitten, ...), or a mental property (seeing a bat, imagining flying, thinking about going to the store, feeling bitten, ...).  In the sense intended by defenders of the gap, I think, the last of these is conceptually fundamental.  As we might say, there isn't anything it is like simply for a creature to be a bat, or human, or itself.  To say the least, we ordinarily think it possible for a bat or a human being to spend its entire life in a deep coma, with only autonomic brain activity and no consciousness of any sort, while still being a bat or a human being.  Similarly, there isn't anything it is like for a creature simply to fly, to go to the store, or to be bitten--where these are construed as purely bodily and environmental features.  A deeply comatose bat can be flung through the air, and its teeth can be sunk into a deeply comatose human being who is being carried to the store.  When there is something it is like to have a kind property or a bodily or environmental property, this is explained by there being something it is like to have a mental property--indeed, something it is like simply to have the mental property.  Perhaps there is something it is like simply to see a bat, to imagine flying, to think about going to the store, or to feel bitten--at least when these are active and introspectible mental features.  Creatures without such mental properties--perhaps the deeply comatose--need not apply. 

            Suppose then that a creature c has a mental property M.[1]  How can we get at the concept of conscious experience that defenders of the explanatory gap seek to isolate?  I will begin (but not end) by investigating why the following (somewhat) ordinary expression strikes the right conceptual chord in so many people:
   (1)     There is something it is like to have M.
Although I do not assume (or deny) that linguistic analysis is the best inroad into concepts, this methodology seems especially relevant here, since there must be some explanation for the striking fact that defenders of the gap rely almost entirely upon (1) and its slight variants at almost every crucial turn.[2]  To determine what concepts this phrase expresses, it would help to determine the contributions of the component phrases 'there is,' 'something,' 'it,' 'is like,' and 'to have M.'  What conceptual roles do these play?  I will reserve the fishy 'something' and 'is like' for last, and consider the other phrases as preliminaries.  First, however, I would like to register two stipulations about the force of claim (1), in order to ensure that it is taken at full strength. 

Two overarching requirements 

            To my ear, (1) can be heard either as entailing that M is actually and currently possessed--perhaps with the emphasis 'there is something it IS (now) like to have M'--or as making a claim about possible cases of having M--perhaps with the emphasis 'there is something it is like (simply) TO have M.'  Since my aim is to take the explanatory‑gap challenge as seriously as possible, I want to ferret out any and all content that may be suggested by the pet phrase of gap‑defenders.  So I will construe (1) as making a claim both about the actual (present) case and more broadly about possible cases.  The broader claim is not merely that there is a correlation between there being something it is like, on the one hand, and the possession of M, on the other.  It is that there is something it is like simply to have M--that there must be something it is like in order to have M.  Consider again the hesitation or looseness we sense about 'it is like something to be a bat' or 'it is like something to go to the store'--as opposed to 'it is like something to feel pain'--as described in the first paragraph of this section.  This is a sign that a necessity claim is suggested by (1).  The hesitation or looseness might be explained as follows: we deny 'in order to be a bat, there must be something it is like,' and 'in order to go to the store, there must be something it is like,' but perhaps we affirm 'in order to feel pain, there must be something it is like.'  This necessitation requirement is never far from the surface, since we can favor it merely by emphasizing the word 'to' in (1), as above.  On a natural reading this is elliptical for 'in order to.'  On this reading, for (1) to be true:
   (α)     M must be (actually, currently) possessed, and
(β)     as a necessary condition for (α) there must be something it is like.
I will not try to make these overarching requirements explicit by expanding (1), but I will appeal to them from time to time, and they are to govern every expansion of (1) below.[3] 

'There is', 'it', and 'to have M' 

            Let us turn to the component phrases of (1).  First we have to note that (1) is clearly elliptically equivalent to (2):
   (1)     There is something it is like to have M.
   (2)     There is something it is like for c to have M.[4]
The 'for c' plays multiple roles simultaneously.  The two most obvious roles depend on whether 'for c' forms a unit with the phrase following it or the phrase preceding it.  We can read (2) both as 'it is like something for‑c‑to‑have‑M' and as 'it is‑like‑something‑for‑c to have M.'[5]  In the former case, 'for c' is redundant given that c is M's bearer; on this reading it can be omitted without noticeable semantic loss--as in the Levine and Chalmers quotes above, yielding (1).  But it also plays the more substantive latter role; on this reading, it can be stressed without noticeable semantic gain--as in Nagel's emphatic "something it is like for the organism" in the quote above.  (The stress encourages the second reading, but this reading is available without the stress.)  The best way to make these two roles explicit is to duplicate 'for c,' construing (2) as equivalent to (3):
   (2)     There is something it is like for c to have M.
   (3)     There is something it is like for c, for c to have M.
Next, consider two possibilities for the role of 'it.'  Sometimes a phrase‑initial 'it' is merely for grammatical show, as in 'it is raining' or 'it stinks.'  We typically use this bare 'it' when we refer to a property‑instantiation without having identified a bearer of the property--for instance, when we don't yet have a view about what stinks, or when there isn't anything (that needs mentioning) that is raining.  But the 'it' in (1)-(3) seems quite unlike these--it purports to refer to the bearer of the property of being like something for c.  One symptom of this more substantive use of 'it' is that the predicate 'is like something' can be completed with 'to ...,' where the ellipsis completes a verb phrase, as in (1)--'it is like something to have M.'  We cannot say 'it is raining (for one) to [verb]'.  We can say 'it stinks (for one) to [verb],' but only when we mean that (one's) [verb]ing stinks.  As a comparison, the sentence 'it is fun (for one) to teach' is equivalent to '(one's) teaching is fun (for one).'  So (3) is equivalent to (4):
   (3)     There is something it is like for c, for c to have M.
   (4)     There is something c's having M is like for c.
As a final preliminary, note that there is nothing that 'there is' adds to the zing of (1)-(4), since (4) is clearly equivalent to (5):
   (5)     c's having M is like something for c.
Here is what we can glean from these preliminaries and the overarching requirements (α) and (β): whatever property (if any) being like something for c is, (1)-(5) express that it is possessed by c's having M, and necessarily so (given that c has M at all).  One of (1)'s attractions is that it  expresses this conceptual material so compactly and fluidly. 

'Is like' and 'something' 

            Let us turn finally to the peculiar phrase 'is like something for c.'  The 'something' plays an especially odd role.  It clearly functions as a variable, a placeholder, but over what does it generalize?  Not primarily "things" designated by noun phrases, but features specified by predicative phrases.  If asked what it is like to wrestle with a riddle, the adjectives 'interesting' or 'fatiguing' are better answers than the nouns 'interest' or 'fatigue.'  This use of 'like' in (1)-(5) mirrors a more widespread use described as follows in the 1971 Oxford English Dictionary (O.E.D.):

Some phrasal uses of the adj[ective] ['like'] in this construction ['is like'] have a special idiomatic force.  The question What is he (or it) like? means 'What sort of a man is he?', 'What sort of a thing is it?', the expected answer being a description, and not at all the mention of a resembling person or thing.  (Like, adj., A.1.b., L‑283)

If we were to try to express (5) in something more like logical notation than grammatical English, we would have to write 'is like some F'--using a predicate variable 'F'-- rather than 'is like some x'--using a term variable 'x.'  But it is only in rare cases that we can complete 'is like ...' with a predicate rather than a term, without losing grammaticality.  We can say a mental state 'is like interest and fatigue' but not that it 'is like interesting and fatiguing,' except when 'like' is, like, a mere interjection, as it clearly is not in (1)-(5).  However, we can say, with only a slight awkwardness, 'it is like something--interesting and fatiguing' or 'interesting and fatiguing are some things it is like.'  Let us record as follows the very odd pair of grammatical properties displayed by 'is like' and 'something' in (1)-(5):
   (a)     'something' is best specified by predicates, not terms, yet
   (b)     predicates typically cannot grammatically follow 'is like.'
I will return to the rare exceptions to (b) later, exceptions such as 'is like mad' and 'is like new.'  A further piece of evidence for (a) stems from the philosophical jargon of 'qualia' and 'phenomenal properties,' which defenders of the explanatory gap (and others) introduce by the following stipulation:
   (c)     qualia and phenomenal properties are what in particular it is like to have mental states.
Grammar aside, qualia and phenomenal properties are the particular "things" it is like to have certain mental states.  But qualia and phenomenal properties are, of course, properties--if they are anything at all.  These "things" are ways of being--values of 'F'--as opposed to ordinary beings--values of 'x'.  Somehow, despite the ungrammaticality, 'is like something' comes to 'is like some way' rather than 'is like some thing.'[6] 

            I believe that (a) and (c) are genuine semantic features that must not be lost in interpreting (5), but that (b) is a relatively unimportant accident of modern English syntax.  Although with the exception of 'is like mad' and 'is like new' we do not often say 'is like F'--not even 'is like sane' or 'is like old'--such phrases were once more common in English.[7]  It is no surprise that they would be rendered obsolete, given the dominant competing use of 'is like' for 'is similar to,' which demands completion by terms (for instance, nouns) rather than predicates (for instance, adjectives).  Yet while 'is like [adjective]' has lost its head‑on competition with 'is like [noun],' it lives on in the simple variant 'is [adjective]-like.'  The O.E.D. describes modern Scotch usage in ways that seem tantalizingly relevant to the present quest:

In Sc[otch] the suffix ['-like'] is added freely to almost any descriptive adj[ective], esp[ecially] those relating to mental qualities, conditions of temper, or the like; the general sense of the compounds is 'having the appearance of being --'.  (-like, suffix, 2.a., L‑287)

Modern (19th‑ and 20th‑century) examples given include "greedy-like," "grim-like smile," "square‑like room," "herbaceous-like shrub," "sublime-like beauty," "gluey-like material," and so on.  This usage is not only a survival of earlier Scotch usage,[8] but of a much more extended usage in English: in fact, the ubiquitous use of the suffix '-ly' for adverbs derives from the Middle English suffixes '-lik' and '-like,' as in modern English 'greedily' from Middle English 'gredilike.'[9]  Modern English also has a small number of survivors such as 'genteel-like' and 'humanlike.'  Frequency and breadth of use aside, the important point is that these constructions are all easy for the ordinary speaker to understand.  I believe that the best way to make sense of grammatical features (a)-(c) is to interpret (5) as (6):
   (5)     c's having M is like something for c.
   (6)     For some F, c's having M is F-like for c.
As quoted above, the O.E.D. identifies the general meaning of 'is [adjective]-like' as '[has] the appearance of being [adjective]' (-like, suffix, 2.a., L‑287).  Given this definition, (6) in turn is equivalent to (7):
   (7)     For some F, c's having M has the appearance of being F for c.[10]
To counter the application of the O.E.D.'s definition to (6), what is required is some better way of understanding '[adjective]‑like.'[11]  I think it is difficult to motivate a plausible rival interpretation.  Being F‑like presumably does not amount simply to being F; if it did, '‑like' would be idle and (6) would be trivially true ('for some F').  Nor does it seem to require being F; if it did, '‑like' would be entirely misleading.  Certainly there are uses of '‑like' that are not to be explained in terms of "appearances" but in terms of "similarity" more generally construed--for instance, for imperceptible entities such as "electron-like particles" and "Platonic‑Form‑like universals"--but in these cases '‑like' attaches to nouns rather than to adjectives.  A similarity construal of 'like' does not make good sense for '[adjective]‑like,' since c's having M may appear (to have the property) F but is hardly similar to (the property) F.  I discuss "similarity" interpretations at much greater length in section 3 below. 

            Of course, 'appear' and 'appearance' can have a variety of meanings, and much of the remaining task is to select the relevant one and stick with it without equivocating.  For example, I have not yet discussed whether "having an appearance" in the sense relevant to (1)‑(7) must be a matter of actually appearing or as a matter of being disposed (in some sense) to appear.  Nor have I discussed what kind of appearing is involved--for instance, perceptual appearance versus appearance in judgment, and phenomenal appearance versus nonphenomenal appearance.  Before addressing these issues, I want to support the invocation of (7) with some supplementary grammatical considerations. 

'For' and 'c' 

            A semantic virtue of the "appearance" reading (7) is that it makes sense of the conceptual role of 'for' in 'x is like something for c.'  Out of the 31 major uses of the preposition 'for' listed in the O.E.D., there are only two that make much sense in this construction: "in the presence or sight of" (For, prep., A.I.1.b, F‑409) and "as regards, with regard or respect to, concerning" (For, prep., A.IX.26, F‑412).[12]  There are good reasons for thinking "in the presence or sight of" is especially relevant.  First, if 'for' meant only "with regard to," we should expect that it could be followed by terms other than those for creatures.  A pain in my leg is "with regard to" me, but it is also "with regard to" my leg, my medicine cabinet (since it sends me hobbling there), and so on  Nevertheless, the pain in my leg is like something only for me; it is like something neither for my leg nor for my medicine cabinet.  This is explained on the "in the presence or sight of" reading of 'for': the pain in my leg is like something in the sight of me, but not in the sight of my leg or my medicine cabinet.[13]  Second, I think we can only understand the substantiveness (versus redundancy) of 'for'--the fact that it can call for emphasis, as Nagel shows--on the "in the presence or sight of" reading.  Given that c is the creature that has M, features of c's having M are trivially 'for' c in the "with regard to" sense--they are trivially "with regard or respect to" c.  Whatever being like something is, if one knows that a mental state of c's has that feature, one would learn nothing further by being told that this fact is 'for' c in the weak sense that it is "with regard to" c.  One would learn something very interesting, well worth stressing, if one were told that this fact is 'for' c in the sense that it is "in the presence or sight of" c.  Only in that case, as Nagel would urge, have we characterized c's point of view.  This protects (7) as an interpretation of (6) even if--somehow, contrary to the O.E.D.'s suggestion--'is F‑like' in (6) does not itself mean "has the appearance of being F."  We should still interpret the 'for c' in (6) strongly, as (6a):
   (6)     For some F, c's having M is F-like for c.
   (6a)   For some F, c's having M is F-like in the presence or sight of c.
On its own various readings, this is easily seen to be equivalent to versions of (7). 

            Another virtue of the "appearance" reading (7) is that it explains why there is no significant difference between 'is like' as used in (1)‑(5), and corresponding uses of 'feels like' or 'seems like.'  People do not ordinarily distinguish between "what it is like to go on a safari" and "what it feels like to go on a safari," or between "what it is like to be an accountant" and "what it seems like to be an accountant."  Likewise, it is hard to find a difference in meaning among (1) and two variants, as they would ordinarily be understood:
   (1)     There is something it is like to have M.
            There is something it feels like to have M.
            There is something it seems like to have M.
It might be supposed that the "feels" and "seems" claims favor actual appearing rather than mere dispositions to appear, while the "is" claim is more neutral.  But in fact 'feels' and 'seems' can be used dispositionally--'the dark side of the moon feels [/seems] cold' can be true, even when nobody's there--and in fact (as I will argue below) the "is" claim has further grammatical features that disguise an actuality (versus dispositionality) requirement.  Similarly, there is no difference among (5) and two variants:
   (5)     c's having M is like something for c.
            c's having M feels like something for c.
            c's having M seems like something for c.
In these cases 'feels' is used not specifically for "appears to the touch" but more broadly.  This is what allows Chalmers to characterize conscious experiences as those with a "feel," as quoted above (see section 1) and as in his statement (1996, 11): "On the phenomenal concept, mind is characterized by the way it feels; on the psychological concept, mind is characterized by what it does."  Although there is something loose about saying one "feels" one's mind, 'feels' serves better than 'looks' ('sounds,' 'smells,' and so on) because it is used for proprioception.  Proprioceptively feeling one's body serves as an intuitive analogy for introspectively "feeling" one's mind because neither process detours noticeably through the environment.  Also, in these cases 'seems' is not used broadly for "is judged to be"--perhaps due to testimony or wild speculation.  Both 'feels' and 'seems' are best rendered as "appears," with its general perceptual connotations.  As the O.E.D. explains, 'is like' is on occasion used in place of 'looks like'--more generally, in place of "certain idiomatic uses [of 'like'], chiefly with the [verbs] feel, look, sound," (Like, adj., A.7, L‑284)--and "means 'to have the appearance of being' so‑and‑so" (Like, adj., A.1.b, L‑283).  So for reasons independent of (6) or (6a), in addition to those based on the routes through (6) and (6a), (5) is equivalent to (7):
   (5)     c's having M is [that is, appears] like something for c.
   (7)     For some F, c's having M has the appearance of being F for c. 

            Let us now consider what sense of 'appear' in (7) best accounts for the relevant sense of 'is F-like' in (6).  I think this is a very demanding sense.  Notice, first, that the 'for c' at the end of (6) is detachable in inference.  Just as (2) entails (1), there is an entailment from (6) to (6b):
   (6)     For some F, c's having M is F-like for c.
   (6b)   For some F, c's having M is F-like.
In order for x to be F-like--for a creature to be humanlike, for a smile to be grim-like, for a car to be like new, and so on--it is not enough that there be (dispositions to) judgments that x is F--that the creature is human, that the smile is grim, that the car is new, and so on.  Some irrelevant (dispositions to) judgments are based solely on rumor, lies, or wild guesses about x.  As ordinarily understood, rather, x must be perceivable as F--the creature must be perceivable as human, the smile must be perceivable as grim, the car must be perceivable as new, and so on.  But even this is not demanding enough: x is not F‑like if it is perceivable as F only by people with radically defective or abnormal perception.  Of course, it is not required that x actually has the feature F--humanlike creatures needn't be human, grim‑like smiles needn't be grim, cars that are like new needn't be new, and so on--but in some middling sense the appearance as of F-ness must be objectively x's own.  The F-like thing must have a range of easily perceptible features in common with an F thing, enough so that in conditions fairly good for perceiving whether something is F, someone who (nondefectively and normally) perceives these features would to some degree be disposed to perceive x as F, or at least would to some degree be disposed to believe x to be F if the perceptions were taken at face value.  The requirement is partly counterfactual; x may be F-like even when it is not actually perceived at all.  We can summarize all this by construing 'x is F‑like' as 'due to easily perceptible features of x's own, x is perceptible as F,' or, more briefly, 'x itself has a perceptual appearance of being F.'  In the general case, the corresponding use of 'x is like something' would be equivalent to 'due to easily perceptible features of x's own, x is perceptible as being some particular way' or 'x itself has a perceptual appearance of being some particular way.'[14]  

            Notice, second, that we can easily append to 'is ... like ... for c' in (2)-(6) a restriction such as 'but not for anyone else.'  This is one potentially relevant difference between the use of 'is [adjective]‑like' for conscious experience and the use of it elsewhere--for humanlike creatures, grim‑like smiles, cars that are like new, and so on.  In the latter cases the most natural qualifiers restrict the ease of perception to a group (a car may be like new for consumers but not for mechanics, a smile may be grim‑like for children but not for adults, and so on), while for an experience the most natural qualifier restricts the ease of perception to an individual (the bearer of the experience).  This presents a difficulty of interpretation.  By comparison, what would it mean to say 'the smile is grim-like for c but not for anyone else'?  It can mean that only c can be fooled, because of some defect in c.  Or less plausibly it can also mean that c uses some abnormally keen perceptual faculty that no one else in similar circumstances would share.  But when it does mean either of these things, it is incompatible with the detached claim 'the smile is grim‑like.'  As described in the previous paragraph, the simplified claim requires a kind of objectivity and reference to normal perception.  What would it mean, then, to say 'the smile is grim‑like for c but not for anyone else' in a sense compatible with the objective 'the smile is grim‑like'?  Here, I think, it would be meant that the smile actually perceptually appears only to c as grim (or actually appeared so, with the perceptual memory intact in c), although if others could perceive (the relevant properties of) the smile, they too would perceive it as grim.   

            Likewise, since 'c's having M is like something' is compatible with 'c's having M is like something for c but not for anyone else,' this favors the stronger reading that c's having M actually perceptually appears or (memorably) appeared to c as being some way.  The present‑tense "appears" requirement is favored over the more relaxed "appears or appeared" requirement by an element in (1)‑(7) that is absent in the grim‑like-smile case, namely, the overarching requirements (α) and (β), that c now have M and that the appearance be necessary in order for c to have M.  The persistence of a perceptual memory of having had M, after c no longer has M, could not normally be necessary in order for c to have M.  The requirement is more stringent for experience than for other cases, since a creature's being humanlike is not required for the creature's existence, a smile's being grim-like is not required for the smile's existence, a car's being like new is not required for the car's existence, and so on.  The upshot of all this is that (1)‑(7) are equivalent to (8):
   (7)     For some F, c's having M has the appearance of being F for c.
   (8)     c's having M itself perceptually appears some way to c.
Given (α) and (β), this should be understood as:
   (9)     c's having M itself now perceptually appears some way to c, and this is in order for c to have M. 

            Finally, the 'c' in 'is like ... for c' (and 'appears ... to c') seems to express an additional requirement, which can be reached by emphasizing that it means "c as a whole" rather than "some small part of c."  This sort of requirement is widespread in contemporary discussions, following a suggestion of Gareth Evans that "conscious perceptual experience ... serves as the input to a thinking, concept-applying, and reasoning system," so that "we can say that the person, rather than just some part of his brain, receives and possesses the information" (1982, 158).  Evans' requirement is designed to apply to persons, but perhaps some similar requirement could extend to creatures more generally.  Much more needs to be said about the proper construal of 'as a whole' (see section 5 below), but for now let us record it by construing (9) as equivalent to:
  (10)    c's having M itself now perceptually appears some way to c‑as‑a‑whole, and this is in order for c to have M.
It should be admitted that the appeal to "wholeness" can only be maintained somewhat vaguely.  In biological creatures, probably no mental process, and certainly no particular mental state, is avaliable to the "whole" of a creature.  Some processes and states within a perceptual subsystem may be unavailable to processes of reasoning, and so on, but equally, processes and states within a reasoning subsystem may be unavailable to processes of perception.  It is important to recognize some such vague requirement, however, in the spirit of extracting every ounce of content from the phrase 'something it is like for c.' 


            (10) is my stopgap analysis of the very concept of there being something it is (now) like for a creature c (simply) to have a feature M.  It gives expression to a number of requirements or "specs" for phenomenality:
   (A)    c has M.
   (B)    c mentally represents c's having M as being some way.  [This is part of "appearing."]
   (C)    This representing is necessary for c to have M rather than added to c's having M.
   (D)    This representing is in perception ["an appearing"] rather than merely in (disposition to) judgment.
   (E)    This representing is actual rather than merely counterfactual.
   (F)    This representing is present‑tensed rather than merely in past‑tensed memory.
   (G)    This representing is due to perceptible features of c's having M ["itself"].
   (H)    This representing is for c as a whole rather than for a small part of c.
I have tried throughout to take (1) and its variants in the very strongest ways suggested by their grammar.  There may be weaker readings of (1) that require a subset of (A)‑(H), but at best these yield unclear cases of phenomenality.  At any rate, (A)-(H) are especially appealing because they give expression to the idea, emphasized without end by defenders of the explanatory gap, that conscious experience is subjective rather than objectively independent of a subject's access to it.  If c's having M satisfies (A)-(H), then its being requires its being perceived, in the strongest sense.  This is further evidence that we have not "missed the point" or "defined consciousness away" in analyzing the concepts expressed by (1).[15]   

            The central task ahead is to investigate whether specs (A)‑(H) can be explained satisfactorily by a scientific model.  A satisfactory explanation of (A)‑(H) would explain the truth of (10), which in turn entails (9), which entails (8) ... and so on counting down to (1) itself:
  (10)    c's having M itself now perceptually appears some way to c‑as‑a‑whole, and this is in order for c to have M.
   (9)     c's having M itself now perceptually appears some way to c, and this is in order for c to have M.
   (8)     c's having M itself perceptually appears some way to c.
   (7)     For some F, c's having M has the appearance of being F for c.
   (6)     For some F, c's having M is F-like for c.
   (5)     c's having M is like something for c.
   (4)     There is something c's having M is like for c.
   (3)     There is something it is like for c, for c to have M.
   (2)     There is something it is like for c to have M.
   (1)     There is something it is like to have M.[16]
Using this stopgap analysis we would be able to deduce that there is something it is like to have M, from whatever scientific premises are needed to explain (A)‑(H).[17]  Of course, if an explanation of (A)‑(H) is to yield a satisfactory explanation of (10)‑(1), the term 'appear' must bear the same sense throughout the explanation and throughout the stopgap analysis (as must its cognates: 'appearing,' 'appearance,' and so on).  I consider this issue in sections 4 and 5, and then procede with the search for a scientific account of (10) in section 6.  But first, in the following section, I try in other ways to motivate (10)-(6) as an interpretation of (5)-(1), by considering and rejecting rival interpretations of 'is like something.'  In the process I will describe several further virtues of my interpretation, but readers who are not tempted by the rivals, or who are averse to the technicalities of section 3, may proceed to section 4 at any point. 

3     Scrap 

            Leaving aside uses of 'like' related to the verb 'to like,' the O.E.D. distinguishes two families of uses: as an adjective modifying terms--where 'x is like y' means 'x is similar to y' or 'x resembles y,' and as an adverb modifying predicates--where 'x has F like y' means 'x has F in the manner of y' or 'x has F as y has F' or 'x has F as if x = y.'  Judging solely from what precedes 'like' in (1)‑(5)--'c's having M is ...' (or 'it is ...')--either of these uses could be in play.  'Is like ...' could be an adjective modifying 'c's having M,' so that 'c's having M is like ...' would come to 'c's having M is similar to ....'  Or 'like ...' could be an adverb modifying the being of c's having M, so that 'c's having M is like ...' would come to 'c's having M exists like ...' and therefore to 'c's having M exists in the manner of ....'  Neither avenue is particularly promising, however.  I will discuss the adjectival "is similar to" proposal; the results would apply straightforwardly to the adverbial "in the manner of" proposal.  

            If instead of moving from (5) to (6) we were to try reading 'is like' literally, as 'is similar to,' we would get (5a), an implausibly weak construal of (5):
   (5)     c's having M is like something for c.
   (5a)   c's having M is similar to something for c.
One sign that this is a bad reading of 'is like' is that it does not make sense of the optional detachability of 'for c' described above. The detached claim (1) can easily be heard as elliptical for (2), as the detached (6b) can easily be heard as elliptical for (6).  By contrast the detached version of (5a) is utterly trivial, and does not sound at all elliptical for (5):
   (5b)   c's having M is similar to something.
Each thing is similar to something or other, and in fact, each thing is similar in some respect or other to each other thing.[18]  So in this weak sense each of one's mental states "is like something," no matter how far it may be removed from conscious experience.   

            Of course, for similarity claims relating two specific kinds of entities, there are pragmatic implicatures about relevant respects of similarity.  But there is no such pragmatic substance under generalization, when one of the "kinds" is "something".  By contrast, the interesting thing about 'is ... like' in (1)-(6) is that it maintains substance despite the generality of 'something,' even in detached claims such as (1) and (6b).  This is explained quite simply on the "perceptually appears" interpretation I have given of (5):
   (8)     c's having M itself perceptually appears some way to c.
On my account (5) remains substantive despite the generality of 'something' because perceptually appearing some way is substantive in a way that being similar to something is not.  

            While this detour through the detached (5b) is telling, it is perhaps more important for an interpretation to succeed with undetached claims such as (5a).   Even though a "similarity" reading is trivial for (5b), perhaps it is not for (5a).  Perhaps some "hidden" mental states of mine--latent memories, tacit knowledge, Freudian hatreds, Heideggerian anxieties, subliminal perceptions--fail to be conscious experiences because they are not similar to something for me.  Presumably to ask whether they are similar to something "for me" is to ask whether they are similar to something to me, that is, whether I believe they are similar to something.  Well, since I believe everything is similar to everything else, as soon as I so much as guess that these states exist--say, by reading Freud, Heidegger, or Chomsky uncritically--I believe they are similar to something.  This does not raise them to the status of conscious experiences, however.[19]  (5) should not be interpreted literally, as (5a).  By contrast, my interpretation (8) can explain why there is nothing it is like for c to have these "hidden" states, even when c believes in them via testimony or wild guessing.  It is not even intuitively tempting to think they are perceptible by c. 

            It is unsurprising that 'is like' in (1)‑(5) should be taken nonliterally, given the grammatical peculiarities described in the previous section:
   (a)     'something' is best specified by predicates, not terms, yet
   (b)     predicates typically cannot grammatically follow 'is like.'
As the O.E.D. recognizes, (a) and (b) are signs that 'is like' is "idiomatic" here, and cannot easily be interpreted as the literal 'is similar to' (Like, adj., A.1.b, L‑283; quoted above).  If we try to respect (a) directly--allowing that 'something' generalizes over ways of being--this literal interpretation yields logical gibberish.  (5) would become the absurd (5c):
   (5)     c's having M is like something for c.
   (5c)   c's having M is similar to some way for c.
A state (event, process, ...) such as c's having M is at best only abstractly and unintuitively "similar" to any feature or "way" itself.  There are no gibberish problems affecting my interpretation (8), since 'x perceptually appears some way' is perfectly intelligible in a way 'x is similar to some way' is not.  A similarity reading can avoid (most of) the gibberish as follows:
   (5d)  c's having M is similar to something that is some way, for c.
However, this falls back into utter triviality, since everything is "similar to something that is some way."   

            Further difficulties arise from the widespread philosophical stipulation mentioned in the previous section:
   (c)     qualia and phenomenal properties are what in particular it is like to have mental states.
Given that the ways specifying 'something'--values that potentially determine what it is like for c to have M--are supposed to be troublesome "qualia," there is no way to rescue a literal "is similar to" reading of (5) as in (5d).  My present visual experience of this page has the feature of being in Ann Arbor.  It is therefore similar to something that is in Ann Arbor--in fact, to a great many such things.  But being in Ann Arbor is not a quale; it is not something that my experience "is like" in the relevant sense.  Even if I know that my experience is in Ann Arbor, this feature is not part of what my experience is like "for me" in the relevant sense.  Not all the ways of a conscious experience are qualia, nor even all the ways that are necessary in order for the experience to exist--being self‑identical, being part of a functioning mind, and so on. 

            We cannot even rescue an "is similar to" reading of (5) by building in a restriction to similarity in phenomenal respects (or in qualia), yielding (5f):
   (5)     c's having M is like something for c.
   (5f)   c's having M is similar in phenomenal respects to something that is some way, for c.
First, of course, this would lead to circularity, since defenders of the gap seek to characterize the philosophical jargon 'phenomenal' and 'qualia' in terms of "what it is like," as in (c) from the previous section.  Even if this difficulty were waived, because 'what it is like' and the philosophical jargon are somehow to be characterized jointly, this reading of 'is like' would sever even a correlation between "what it is like" and the philosophical jargon.  Suppose that Q is a legitimate quale, and that Q is "something" my present visual experience of this page is like.  If (5f) is a good reading of (5), then (5f) should apply to my experience with 'Q' substituted for 'some way.'  This is the case--an experience with quale Q is similar in phenomenal respects to something that is Q.  However, my experience with quale Q is also similar in phenomenal respects to something that is Q and in Ann Arbor (or Q and part of a functioning mind).  Nevertheless, being Q and in Ann Arbor is not something my visual experience is like in the relevant sense, not even if I know my experience has the feature.  So not even (5f) is a good interpretation of (5).  (6)‑(10) by contrast can explain why such features as being in Ann Arbor and being Q and in Ann Arbor are not qualia.  Consider that a car that is like new is not like new and in Ann Arbor, even if it is in Ann Arbor, or is nearly in Ann Arbor, and even if everyone knows this.  This is because the car perceptually appears to be in Ann Arbor not primarily due to easily perceptible features "of its own," but also due to perceptible features of Ann Arbor.[20]  Likewise, if my experience appears to be in Ann Arbor (or in a functioning mind) this is not primarily due to perceptible features of its own. 

            If an "is similar to" reading has any remaining plausibility, I think this is because we so easily construe similarity specifically as perceptual similarity--a construal that is even easier for 'resembles'--as in the following potential interpretations of (5):
   (5g)   c's having M is similar in perceptual appearance to something that is some way, for c.
   (5h)   c's having M perceptually appears similar to something that is some way, for c.
For potential purposes of stopping up the explanatory gap, such readings of (5) would be close enough to my own "perceptually appears" reading (8), which I derived independently via (6)-(7):
   (8)     c's having M itself perceptually appears some way to c.
If anything, (8) sets the standard for scientific explanation higher than (5g)‑(5h), since these can be read as appealing merely to counterfactual appearings, while (9) appeals to actual ones.  Neglecting this difference, the three seem equivalent.  To the extent that similarity is most frequently understood, ordinarily, as perceptual similarity, this gives independent support to my stopgap analysis of (1). 

            The strength of 'for c' (described in the previous section) yields another way to protect (7)‑(10) as an interpretation of (5), even if--contrary to my argument from grammatical peculiarities (a)‑(c)--(5) is equivalent not to (6) but to the literal:
   (5a)   c's having M is similar to something for c.
Even if so, we should still interpret the 'for c' in (5a) strongly, yielding:
   (5i)    c's having M is similar to something, in the presence or sight of c.
Leaving aside the counterfactual/actual contrast, this is equivalent to (8).  On the extremely plausible assumption that entities do not appear "similar" unless they each appear some (shared) way, for (5i) to be true c's having M must appear some way to c, so (5i) entails (8).[21]  (8) in turn entails (5i), on the extremely plausible assumption that if x appears some particular way, it appears similar to other things that would appear that way.[22]  So (8) would be equivalent to (5) even if--contrary to what I maintain--(6) is a red herring. 

4     A trap 

            As I mentioned at the end of section 2, in order to stop up the explanatory gap (10) must involve an unambiguous sense of 'appear,' one that is both relevant to conscious experience and explainable scientifically.  According to defenders of the explanatory gap, ambiguity is often the crucial deficiency in attempts to explain conscious experience.  To be on the safe side, then, let us consider how these objections run. 

            Chalmers says that Daniel Dennett (1991) "claims (in effect) that what needs to be explained is how things seem, and that his theory explains how things seem" (1996, 370).  Chalmers objects as follows:

This is an elegant argument, with a ring of plausibility that many reductionist arguments about consciousness lack.  But its elegance derives from the way it exploits a subtle ambiguity in the notion of 'seeming,' which balances on the knife edge between the phenomenal and psychological realms.  There is a phenomenal sense of 'seem,' in which for things to seem a certain way is just for them to be experienced a certain way.  And there is a psychological sense of 'seem,' in which for things to seem a certain way is for us to be disposed to judge that they are that way.  It is in this first sense that a theory of experience must explain the way things seem.  But it is in the second sense that Dennett's theory explains it.  (1996, 190)

I am not concerned here with whether Chalmers' interpretation and criticism of Dennett is correct.  I wish to distance my approach from Dennett's, and to explain how I do not slip between two senses of 'appear' (or of 'seem'), whether "phenomenal" or "psychological" or otherwise. 

            Although the results I have enshrined in specs (A)‑(H) depend heavily on the use of 'appear,' and although this is similar to Dennett's term "seem," the similarities end very quickly.  First, Dennett seeks to explain how things seem--the things comprising the typically nonmental subject matter of experience--while I wish to explain how experience seems (or appears).  I am promoting a kind of inner "theater" model that Dennett has argued most forcefully against (see my 1994 for a defense of theater models from Dennett's attacks).  Second, as is already emphasized in (D), I do not give pride of place to mere (dispositions to) judgments, in the way that Dennett does.  So I definitely do not trade on Chalmers' "psychological" sense of 'seem' (or 'appear').  I do not even assume that this is a bonafide sense of 'appear'--I may judge that the universe is finite, but it does not in any sense I care about appear finite, and at the moment I am disposed to judge of any ripe banana that it is yellow, but at the moment none appears yellow to me.  My sense of 'appear' is far more demanding than the psychological sense of 'seem' that Chalmers finds in Dennett. 

            Given my reliance on the notion of perceptual appearings, which have subject matter or representational content, my view has some affinities with a view that Chalmers calls "representationalism": 

A recently popular position ... has been that phenomenal properties are just representational properties, so that yellow qualia are just perceptual states that represent [that is, perceptual properties of representing] yellow things, or something similar.  Most often, the suggestion is combined with a reductive account of representation (usually a functional or teleofunctional account) ....  (1996, 377)

One difference between my position and ordinary representationalism is that my crucial focus is not on the (perceptual) representing of nonmental "yellow things" but on the (perceptual) representing of representings (that is, of what I will argue are experiences) of yellow things.  The detailed sense in which my position is representationalist will only become explicit in section 7.  For now, what matters is the challenge of avoiding equivocation.  Chalmers' overall criticism of representationalism echoes his criticism of Dennett:

The surface plausibility of some representationalist accounts may well arise from a slide between inflationary and deflationary readings of 'representation,' where the second is a purely functional (or teleofunctional) notion, but the first is not.  The link between phenomenology and representation is made plausible on the first reading, but the reduction of representation is made plausible on the second.  (1996, 377)

Again, my concern is not with the merit of this diagnosis of previous representationalist theories.  I agree that (A)‑(H) must be explained with 'appear' in precisely the same sense that makes (7)‑(10) justified construals of (1)‑(6), to avoid charges of missing the point: 
(6)     For some F, c's having M is F-like for c.
   (7)     For some F, c's having M has the appearance of being F for c. 

            What then is the sense of 'appear' that makes (7)‑(10) plausible as a reading of (6)? My answer is: whatever sense generally makes 'x appears F' a plausible reading of 'x is F‑like.'  What sense is that?  It is certainly not Chalmers' alleged psychological sense of 'seem' (or 'appear').  We do not understand 'the creature is humanlike,' 'the smile is grim‑like,' and 'the car is like new' in any literal way we might understand 'there is a disposition to judge that the creature is human' or '... that the smile is grim,' or '... that the car is new.'  A devious or wildly guessing rumor mongerer (or a used‑car dealer on television) can bring about the truth of the latter statements without bringing about the truth of the former statements.  The relevant sense of 'appear' is, as Chalmers would expect, much more "inflationary."  It is demanding in ways expressed in specs (D)‑(F), requiring actual, present‑tensed perception.  Call this the "perceptual" sense of 'appear' (or 'seem').[23] 

            Although the perceptual sense is much more stringent than Chalmers' alleged psychological sense of 'seem,' it does not involve his alleged phenomenal sense of 'seem.'  The concept of there being something it is like is not presupposed (individually) by the concepts of actuality, presenttensedness, or perception.  I assume this is obvious for the concepts of a state's being actual and being present‑tensed, but perhaps I need to argue that a state can (as a matter of conceptual possibility) be perceptual without being phenomenal.  The intuitive conceivability of perceptual states it is like nothing to have is supported by actual cases of wholly subliminal perception and "blindsight," and of "early" states in processing in the retina, lateral geniculate nucleus, and (perhaps) primary visual cortex.  I do not need to establish here (though in fact I believe) that in some cases there is nothing it is like to have such states, but I do claim that we conceive of them as perceptual without knowing or caring whether there is--and so we speak of subliminal perception, blindsight, primary visual cortex, and so on.[24]  (A critic might emphasize 'blindsight' rather than 'blindsight,' hoping to deflate the idea that this is perceptual.  But in fact I am thrilled to emphasize 'blind.'  Blindsight is not sight in which one is blind--that would be a conceptual contradiction--but sight to which one is blind--this contrasts nicely with phenomenal seeing, if I am right that phenomenal seeing requires perceptually‑apparent‑to‑one seeing.  I discuss blindsight--and the possibility of inner blindsight--more fully in the next section.) 

            The broadly perceptual (rather than any strictly phenomenal) sense of 'appear' is what is relevant to the 'is F‑like' cases: humanlike creatures, grim‑like smiles, like‑new cars, and so on.  For a used car to be like new, it is enough for it perceptually to appear new, whether it does so because of wholly subliminal perception or full‑fledged conscious experience.  As any psychologically savvy used‑car dealer must know, the more subliminal perception involved in the appearance of newness the better (and, indeed, truer) the claim that the car is "like new."  Cars could be like new even for beings as much like us as possible without having phenomenal consciousness--though I do not say they would be philosopher's "zombies" exactly like us in nonphenomenal ways.  The same holds for humanlike creatures, grim‑like smiles, and so on.  At no point along the way to (10) does the stopgap analysis of (1) introduce phenomenal concepts, circularly, and at no point does the power of the arguments depend on implicit assumptions of phenomenality. 

            "But surely there must be a double use of 'appear' somewhere, if it is to forge a link between raw material and raw feels!"  Absolutely.  I do not use 'appear,' fallaciously, with a double sense (meaning, intension, concept, ...)--here with one sense, there with another.  But I do use 'appear,' nonfallaciously, with a double object--here one class of things does the appearing, there another class of things does the same kind of appearing.  First, I appeal to scientific explanations of what it is for arbitrary objects and events (actually, present‑tensedly, and perceptually) to appear.  This appeal certainly does not all by itself explain why there is something it is like to have certain mental states.  Such appearings can and do exist without there being anything they are like.  But second, holding unequivocally to this scientifically explainable sense of 'appear,' I apply it not to arbitrary objects and events but (in ways to be described in section 6) to appearings themselves.  There is only one sense of 'appear' in my account, the perceptual sense.   

            If the sense in which an experience 'appears' to one is to be exactly the same as the nonphenomenal sense in which a car 'appears' to one, without room for a conceptual residue, the two relations had better be commonsensically practically indistinguishable except for the difference in relata.  If we could tell the two relations apart introspectively, or through any other means easily available in commonsense thinking, and if this difference were of any practical concern to us (aside from the difference in relata), then it would be likely that we would have different concepts for them, different senses of the word 'appear.'  To insure that we do not cheat by assuming phenomenality or equivocating in any other fashion, then, let us for emphasis include a conceptual requirement (I) in addition to specs (A)‑(H):
   (A)    c has M.
   (B)    c mentally represents c's having M as being some way.
   (C)    This representing is necessary for c to have M rather than added to c's having M.
   (D)    This representing is in perception rather than merely in (disposition to) judgment.
   (E)    This representing is actual rather than merely counterfactual.
   (F)    This representing is present‑tensed rather than merely in past‑tensed memory.
   (G)    This representing is due to perceptible features of c's having M.
   (H)    This representing is to c as a whole rather than to a small part of c.
   (I)     This representing is indistinguishable from the (not specifically phenomenal) appearing done by ordinary environmental objects (that is, indistinguishable for commonsense purposes and by commonsense methods, except for the difference in relata).
These relations might be distinguishable by scientific methods unavailable to commonsense, or distinguishable in ways that do not matter for significant practical purposes, so long as this does not plausibly affect the ordinary concept of the relations.  

            Judging from the writings of gap‑theorists, philosopher's jargon about the "phenomenal" is simply a way to invoke what 'something it is like' invokes.  If there is a genuine strictly phenomenal sense in which a car "appears" to a subject--and why not?--then presumably it applies when the car appears to the subject in the perceptual sense, and when there is something it is like for the subject to have this perceptual appearing directed at the car.  In keeping with the stopgap analysis of 'something it is like,' then, the phenomenal sense is to be defined in terms of the perceptual sense of 'appear' as applied to the car, together with the perceptual sense of 'appear' as applied to this perceptual appearing itself--inner perception of outer‑perceptual states.[25]  This does not mean that I am explaining normal phenomenal perception as simply subliminal inner perception, or inner blindsight.  The other elements of (A)‑(I) must be satisfied as well, yet subliminal inner perception and inner blindsight would not clearly be inner perception "for the creature as a whole," at least not in creatures with "central" or "global" processes of judging, reasoning, deciding, and so on.  I explain this further in the next section. 

5     A handicap 

            Blindsight subjects have portions of their visual field--"blindsight regions"--in which they deny that they have conscious experiences of specific stimuli.  However, in some sense they have perceptual states sensitive to these stimuli--"blindsight states."  For example, some ability to discriminate an 'X' from an 'O' is intact.  This is evidenced by the preponderance of correct answers they can give to questions about the stimuli.  When asked to reach for objects in blindsight regions, also, some subjects reflexively pre‑orient their hand and fingers in ways suited to the specific shapes of the objects.  Since most philosophers writing on consciousness seem to agree that blindsight subjects lack phenomenal perception of specific stimuli in blindsight regions, there have been many recent attempts by philosophers to specify why not--to specify in a systematic way the key deficits in blindsight and related conditions.  What is clear is that the subjects typically lack at least the following features, with respect to blindsight states: higher‑order beliefs (that they are having experiences or perceptual states of any sort), ability to report (on what is perceived), spontaneity in initiating action (they must be coaxed into responding--their reflexes and general behavioral processes may be intact, but even if they desperately want to touch an 'X,' they won't reach on their own for an 'X' in their blindsight regions), and self‑confidence (even when prompted to respond, they say they are only "guessing").   

            These are clues that blindsight states are not "for" a person as a whole.  Robert Kirk has made use of this suggestion in his own attempt to respond to the explanatory gap.  He considers perceptual processing to be nonphenomenal if it occurs within specialized "subsystems whose internal workings are more or less closed off from the rest of the system":

We could perhaps describe ... lower‑level perceptual analysis as ... a kind of interpretation.  However, in itself it doesn't constitute interpretation by the system as a whole.  The presence of elaborate analytical processes of that kind is consistent with the system as a whole being unaware of the features being analyzed.  (1994, 141)

By contrast, he holds that "patterns of stimulation" have what he calls "raw feeling" just in case they "feed into the central regions of the whole system where the processes of assessment and decision‑making take place--those processes which initiate and control the whole system's behaviour" (1994, 142).  There are two elements that should be distinguished in this account: effects on "assessment and decision‑making," and effects on "the whole system's behaviour."  These are not the same.  Even when processes and states within a perceptual subsystem control behavior independently of decision-making, the behavior is surely "the whole system's behavior"--when a creature reflexively ducks, the whole creature ducks, when a frog reflexively catches a fly, the whole frog catches the fly, and so on.  Similarly, blindsight states do have control over behavior of the whole blindsight subject--verbal guesses, preparatory hand orientations, and so on.  The fundamental sense in which blindsight states fail to be for the person as a whole is likely to be cognitive (and conative) rather than behavioral.  The feature of cognitive and conative processes relevant to "wholeness" is that they draw upon and coordinate much of the mental and physical activity of a creature.  They are "central" or "global" processes (see Fodor 1983). 

            If blindsight states can fail to be "for a creature" in these ways, then presumably--if inner perception is possible at all--inner‑perceptual states can also fail to be for a creature as a whole.  This would be inner blindsight.  Inner blindsight of c's having M would not satisfy (10)‑(1), at least on interpretations that take (1) and its variants most seriously and strongly.  States perceived in inner blindsight would not clearly be like something for a creature as a whole.[26]  The inner perception of a state must be poised for wide influence on cognition and conation, to satisfy spec (H) clearly. 

            This raises the question: if (outer) blindsight states were endowed with influence on central cognitive and conative processes, wouldn't this be sufficient for phenomenality, without any need for inner perception?  Certainly inner‑perception requirements are in disfavor among philosophers who emphasize "central influence" and "global control" requirements (Kirk 1994; Dretske 1995; Tye 1995; Chalmers 1996).  Nevertheless, I think that influence on central processes--global control, being for one as a whole--would be a poor account of what makes a state phenomenal, if taken alone.  There are actual examples that support the intuitive conceivability of states that are for one as a whole but not like something for one as a whole.  Elsewhere (1996) I argue that many states with global control do not have qualia, states such as introspectible propositional attitudes and introspectible moods.  At best, these states are merely accompanied by other states with qualia.  For example, there is nothing it is like (even consciously) to believe that snow is white, although on occasion there may be something it is like when one (consciously) believes that snow is white.  There may be qualia associated with imagining saying 'snow is white' in an assertive tone of voice, or visually imagining a white expanse of snow while having a relaxed feeling (breathing easily), and so on.  But none of these perceptual or imaginative states are the belief--the belief itself persists unchanged when they expire or change--and there seems to be no qualia left over for the belief itself to have.  Even when attitudes and moods have global control for one as a whole they do so without presenting a perceptual appearance of their own for one as a whole.  According to the stopgap analysis, this is why they are nonphenomenal.   

            Similarly, if (outer) blindsight states were endowed with global control as attitudes and moods are, without being endowed with perceptual appearances of their own, I do not think this would be sufficient for there to be something it is like to have them.  Such cases have been discussed under the name 'superblindsight' (Block 1994; Tye 1995).  Perhaps a blindsight subject could be trained to "guess" all the time about the stimuli in blindsight regions (yielding reportability and spontaneity), and could meet with great success and encouragement (yielding self-confidence), and could be misinformed that this is how everyone normally goes about life (yielding belief that he has experiences just like everyone else, in his blindsight regions).  All this could happen without a quale in sight, because, I think, inner perception is still missing--like attitudes and moods, his states would exercise global control without having a perceptual appearance for him.  As with attitudes and moods, superblindsight states would be for a person but not like something for the person.[27] 

            It is a good thing, for the stopgap analysis, that central availability (global control, being for one as a whole) is not alone sufficient for a state to be phenomenal.  This means that the concept of central availability is not covertly a phenomenal concept, any more than the concept of actuality, present‑tensedness, and perception.[28]  It is only when these are all taken together, and with the remaining specs (A)‑(C), (G), and (I), that they are conceptually sufficient for phenomenality.  All of the ingredients of my account are active: for a state (clearly) to be phenomenal, it must itself (actually and presently) perceptually appear some way to its bearer‑as‑a-whole (in order to exist at all).  Neither inner perception of a state without central availability, nor central availability of the state without inner perception, suffice clearly for phenomenality of the state.  A state that has global control, but that is not innerly perceived, is perhaps for the creature but not like something for the creature.  A state that is innerly perceived, but not in a centrally available way, is perhaps like something but not like something for the creature.  Only as a unit does centrally available inner perception insure that the state is like something for the creature.  The phenomenal is to be defined wholly as a combination of the nonphenomenal.[29] 

6     A map 

            In this section I want to sketch how requirements (A)‑(I) can be satisfied by a psychological model built only from individually nonphenomenal components.  I do not contend that this is the only way to satisfy (A)‑(I), but I do think it is the most plausible way, and indeed I have defended it extensively elsewhere (1994, 1996, 1998, Forthcoming, and In Preparation), on grounds completely independent of my stopgap argument.  These independent reasons provide some reason to think the model actually fits our psychology, but for present purposes of countering philosophical speculations of an explanatory gap it is enough if the model is possibly accurate.  Likewise, since my aim in this article is to describe how consciousness can possibly be explained satisfactorily, empirical objections to the model are, strictly speaking, irrelevant.  Nevertheless, to broaden the outlook, at the end of the section I address some of the most influential empirically‑based philosophical objections to the model. 

            The specs are meant to insure that there is something it is like for a creature c to have a feature M.  Spec (A) is simply that c have M.  I will not linger over this requirement, since if there is any mystery about how creatures can have features, this arises throughout metaphysics and is not specially raised by problems of mind or consciousness.  There is one potential worry, however.  We cannot begin a noncircular account of phenomenality by assuming that c has what we identify as a phenomenal experience.  To avoid smuggling in assumptions of phenomenality, we should begin by identifying M nonphenomenally.  Then, if all the other requirements can be met, it will have been argued that there is something it is like for c to have M, which is to say, it will have been argued that c has a phenomenal experience in having M. 

            Spec (B) is that c mentally represent c's having M as being some way.  Philosophers have offered many theories of the mental representation relation which do not presuppose phenomenality, and which are "naturalistic" in the sense that they can be pressed into service in providing scientific accounts of the mind.  These accounts are in terms of some mix of causation, correlation, information, inferential role, conceptual structure, verification, evidence, teleological function, psychological explanation, interpretation, translation, similarity, and so on (some influential articles are collected in Stich and Warfield 1994).  For example, on (crude) causal theories, mental states of a given semantic kind represent certain of their ideal or standard causes or effects, and on (crude) correlation theories, mental states of a given semantic kind represent certain conditions that they ideally or standardly or historically correlate with.  I do not commit to any particular theory of mental representation, but instead offer an abstract account meant to be combinable with any of these accounts.  If for some reason it turns out that mental representation cannot be explained scientifically, then this will infect phenomenality in turn.  (This is one of the respects in which what I offer are merely stopgap measures towards explaining conscious experience.)  I do wish to emphasize two things about the form of spec (B).  First, (B) does not require that c attends to c's having M; there can be unattentive representation--for example, of background events in the periphery of one's visual field (this is also an example of unattentive perception).  Second, while c must represent c's having M, c need not represent it as c's having M.  Just as a cow can appear to one without appearing to one as a cow, so a mental state can appear to c without appearing as a mental state.  Nothing in the stopgap argument requires inner perception to be infallible or complete about the mental states comprising its subject matter.  As I indicate below, on a proper formulation of an inner‑perception theory the represented features of an experience are "projected" onto bodily or environmental objects, in ordinary perceptual experience. 

            The difficulties specific to phenomenal consciousness begin with the puzzling spec (C), that c's having M must appear some way to c in order for c to have M at all.  How on a scientific account could a state's being require its being perceived in this way?  If there is even the slightest distinct mechanism by which c's having M brings about an appearance to c, there is room for the mechanism to break, and so the appearance would not be necessary for c to have M.  One possibility is for c's having M somehow to be "reflexive" or to represent itself (in addition to representing other things, such as cars), without any distinct mechanism of reflexive representation.  Something like this view is rife in the phenomenological literature, beginning with Brentano: "[t]he presentation which accompanies a mental act and refers to it is part of the object on which it is directed" (1874, 128).  Nevertheless, there is cause for concern about a reflexivity story given the larger aims of scientific explanation.  Reflexive representation coheres poorly with more general naturalist theories of (referential) content in philosophy of mind.  It doesn't fit with causal theories, since no mental state, not even a conscious experience, causes or is caused by itself.  It also doesn't fit with correlation theories, since every mental state, even a nonconscious nonexperience, correlates perfectly with itself.  How can it be that less than all mental states--and more than none--are reflexive in whatever way is allegedly relevant to phenomenal consciousness?[30]   

            We can avoid this awkward question, and satisfy (C) in a (slightly) different manner, if we treat c's having M as being composed of two states: an "outer‑directed" state (representing, say, a car), and an "inner‑directed" state (representing the outer‑directed state).  In this way the combined state of c's having M "appears" some way in the sense that one of its components appears some way--just as a car can appear some way in the sense that one of its parts (say, its surface) appears some way.  This componential picture seems preferable to a mechanism‑less reflexivity picture, given naturalistic theories of representation, since the inner‑directed states can be caused by or can correlate with their subject matter (the outer‑directed states).  Of course, if the componential strategy is to be more than a cheap terminological trick, we need reasons to believe that inner‑directed states and outer‑directed states are in a substantial way "unified" so that it is psychologically appropriate to treat them as components of a single larger state (c's having M).  I will describe some of these reasons below (see note 37). 

            Given either the reflexivity or componential models, the next difficulty is to satisfy spec (D)--to explain how the representing of c's having M can be perceptual.  It is a familiar commonsense idea that, in addition to being able to have "outer perception" of nonmental entities in one's environment and body, one can "innerly perceive" one's mental entities, as when one seems to see visual images with one's "mind's eye."  It is also the most prominently and frequently recurring idea in the history of philosophical thinking about consciousness, ever since Descartes placed consciousness squarely on the philosophical agenda.  In An Essay concerning Human Understanding Locke writes that "[c]onsciousness is the perception of what passes in a Man's own mind" (1689, 115; II, I, 19); he holds that this faculty of reflection, "though it be not Sense, as having nothing to do with external Objects; yet it is very like it, and might properly enough be call'd internal Sense" (1689, 105; II, I, 4).  Leibniz recommends in The Principles of Nature and Grace, based on Reason that "it is well to make a distinction between perception, which is the inner state of the monad representing external things, and apperception, which is consciousness or the reflective knowledge of this inner state itself" (1714, 637), and Kant refers to this in Critique of Pure Reason as "empirical apperception" of a "flux of inner appearances"--mentioning that "[s]uch consciousness is usually named inner sense" (1787, 136; A 107).  This commonsense familiarity and philosophical tradition (both largely prescientific, at least in relation to sciences of mind) befits a view meant to connect with our ordinary concept of conscious experience.  Yet while inner perception has some contemporary defenders, most notably David Armstrong (1980), it faces several serious objections, and most philosophers of mind see it as a misleading metaphor fit only to be cleared away at the start. 

            How is inner perception supposed to be distinctively analogous to outer perception?  Is there an illuminating analogy?  Armstrong explains inner perception as being, like outer perception, "selective" (incomplete, about the mind or environment), "fallible," and "causal."  This is not much of an analogy, since probably all cognitive processes have these features.  Even one's most theoretical scientific beliefs, for example those about quantum‑mechanics or cosmology, are selective, fallible and causal, without being perceptual in any interesting sense.  So, what could be perceptual about inner perception?  Of course, inner perceptions are not generated by literal inner eyes and ears.  On the other hand, if they are produced by some distinctive faculty of inner access, a theory needs to justify calling the products of this access inner "perceptions" rather than mere inner "reactions" of some other sort.  An initially tempting idea is that inner perception is a causal but noninferential source of evidence about mental states (or, more cautiously, that it is as low as outer perception on flexible, all‑things‑considered inference).  But we must do better if we are to satisfy spec (I), that inner perception be commonsensically indistinguishable from outer perception.  We must avoid even the slightest ambiguity on 'perceptually appears.'  A mere analogy between outer and inner perception will not suffice. 

            I think the clearest way to satisfy (I) is to suppose that inner "perceptions" are literally states of the various outer‑perceptual systems themselves, rather than being states of a distinctive inner faculty.  This would make available a strong sense in which the products of inner perception can be perceptual, counting as visual, auditory or other perceptual states, with minimal violence to the ordinary use of these terms.  Although there are outer sense organs that produce outer perceptions, there need not be inner sense organs that produce inner perceptions.  Once inner perceptions are produced, in whatever way, they are processed like outer perceptions, as further states in particular sense modalities.  For example, inner perceptions in vision help to produce visual beliefs, help to control visuomotor skills, and--most importantly--are not introspectively distinguished in kind from outer perceptions in vision.[31]  They may qualify as perceptual due to their use, even if not due to their origin (since there are no inner eyes and ears), just as "perceptual imaginings" count as perceptual without being caused by sense organs.  The account I offer makes no commitments about the internal structure of the process of inner perception.  The mechanisms (if any) by which outer‑perceptual states cause inner‑perceptual states are not what make the latter perceptual, in my opinion.  Whether these mechanisms involve literal inner sense organs, or (hardwired or flexible) neural connections, or some kind of inference, or switchboard operators (see note 27)--all this is irrelevant to what it is like to have the triggering and resulting states, so long as the process (if any) is hidden from introspection, and is thereby indistinguishable from the structure of outer perceptual processes, in accordance with (I).[32] 

            Call the states (hypothetically) produced by inner perception 'I‑states,' since they are typically inner‑directed (or about one's own mental states).  Similarly, call (hypothetically) innerly perceived states 'O‑states,' since they are typically outer‑directed (or about things other than one's own mental states, such as cars and one's limbs).  The 'O' may also express their status as representational "objects" of inner perception.   

            I assume there is no special problem about satisfying specs (E) and (F), that the representing of c's having M must be actual and present‑tensed.  Even if I‑states are caused by O‑states, and so have their onsets after O‑states do, this does not mean they represent O‑states as in the past.  The temporal relations between I‑states and O‑states are like those between O‑states and environmental objects.  One sees a banana or a star as existing now even though the available information from the banana or star is in some sense "retrospective." 

            To satisfy spec (G) it is necessary that there be features of O‑states that are represented by I‑states.  Which features could these be?  Here I will be quite noncommittal, since the details depend on the correct theory of reference and, lest we forget, the empirical details of neural functioning.  On a scientifically respectable story I‑states may be about intrinsic features of O‑states, such as neural structure, or about extrinsic features of O‑states, such as their causal relations to other mental states (including other O‑states), to sense organs, or to environmental stimuli.[33]  There is no need on my account for I‑states to represent that there are O‑states, or to represent the contents of O‑states.  I do not offer here an inner‑perceptual account of the introspective consciousness (say) that one is seeing a banana.  Instead, I offer an inner‑perceptual account of the phenomenal consciousness that belongs (say) to seeing a banana.  By contrast, I assume O‑states typically represent wholly perception‑free features of environmental stimuli, such as shape, motion, and reflectance.[34]  

            Spec (H) is that the inner perception must be for the creature as a whole, as opposed to being subliminal inner perception or inner blindsight.  As described in the previous section, I think this requirement can be satisfied by (large degrees of) availability of I‑states for systematic impact on central systems of belief and desire.  Of course, this impact should in some sense be in virtue of the content of the I‑states--mere gravitational impact would not suffice, for example.  

            To summarize and illustrate, on this view a perceptual or imaginative experience of a car essentially involves at least the following internal structure (where the solid arrow signifies causation that is required for full‑blown experience, and the dashed arrows signify causation that is typically present but not strictly required):[35] 

In addition, O-states may (and normally, do) have their own outputs to central systems.  As I argue in the previous section, such "direct" outputs are not alone sufficient for phenomenality--innerly unperceived states such as attitudes, moods, and superblindsight states are for the creature but not like something for the creature.  A main reason for postulating an inner‑perceptual component to experience, then, is that this can provide part of an explanation of the phenomenal distinction between normal, conscious, perceptual experience and subliminal perception, (super)blindsight, and early states of the retina or primary visual cortex (however sharp or vague this distinction may be--see note 29).  Phenomenally unconscious perception of a car is like phenomenally conscious perception of a car in generating mental states about the car--states akin to O‑states--but seems unlike phenomenally conscious perception in the absence of any primitive awareness of these states--in the absence of centrally available I‑states.[36]  This plausible (though not completely uncontroversial--see note 24) claim that there can be perceptions wholly lacking in consciousness and phenomenal properties helps to insulate inner perception from its two most influential philosophical objections. 

            The first objection stems from the (wholly proper) denial of "sense data"--phenomenal objects interposed between physical objects and one's perceptions of physical objects.  The worry is that accepting inner perception (especially as part of perceptual experience) would involve accepting that one at best perceives outer objects indirectly through inner perceptions of phenomenal objects in one's own mind (see for example Harman 1990).  My response is that a properly formulated inner‑perception model of experience is not committed to sense data.  Inner perceptions needn't be directed at entities interposed between objects and one's perceptions of them--the causal chain in perceiving a car needn't proceed from the car to an inner perception and then to a perception of the car.  Rather, on a more natural view, the causal chain goes directly from the car to a perception of the car (an O‑state), and then (in cases in which the car‑perception is not merely subliminal) to an inner perception of the perception of the car (an I‑state).  Both outer perception and inner perception are "direct" in the sense of not requiring mediation by further perceptions, and each can have its own independent impact on central systems. 

            Perhaps the most influential objection to inner perception is based on what G. E. Moore calls the "diaphanousness" of perceptual experience:

[T]he moment we try to fix our attention upon consciousness and to see what, distinctively, it is, it seems to vanish: it seems as if we had before us a mere emptiness.  When we try to introspect the sensation of blue, all we can see is the blue: the other element is as if it were diaphanous.  (1903, 450)

The objection is that since each outer‑perceptual modality (seeing, hearing, and so on) makes its own distinctive contribution to what experience is like, an additional modality of inner perception should be expected to make its own contribution, to change what it is like.  But what it is like to introspect a perceptual experience seems simply borrowed from what it is like to have the experience itself (perhaps the best statement of this problem is in Rosenthal 1990).  When one tries to attend to features of normal experiences, one normally "sees through" the experiences to outer objects.  So a fundamental disanalogy between outer perception and alleged inner "perception" is that the former but not the latter has its own phenomenology or perceptual quality.  This is reason to think there is no inner perception of ongoing phenomenal experiences.  My response is based on the idea that inner perception is involved in phenomenal experience from the start.  Contrary to the objection, outer perceptions (akin to O‑states) are not in themselves sufficient for phenomenal experience, which is how there can be states of perception it is like nothing to have (perhaps retinal states, wholly subliminal states, blindsight, and so on).  Rather, on the present account inner perception helps convert ordinary nonphenomenal outer perceptions into phenomenally conscious experiences.  Instead of borrowing phenomenal qualities from outer perception, as the diaphanousness objection alleges, inner perception helps generate these qualities together with (otherwise nonphenomenal) outer perception.  This explains why inner perception doesn't add further qualia to an outer‑perceptual experience: inner perception has already made its phenomenal contribution for there to be an outer experience with phenomenal properties in the first place. 

            Moore's diaphanousness lies behind another source of resistance to the claim that we innerly perceive some of our outer perceptions, even if it is understood that this inner perception is meant to be part of experience.  Perceptual experience represents (nonmental) bodily and environmental objects such as cars, but it does not seem to represent itself.  Doesn't this obvious introspective point undermine an inner‑perceptual model of experience?  Not if we take spec (I) seriously--allowing that inner perception and outer perception are not introspectively distinguished.  Elsewhere (Forthcoming, see also 1996) I argue on independent grounds that there are "binding confusions" between O-states and I-states.  O‑states and I-states represent features that are not in fact had by the same things (at best, O‑states represent features of environmental objects and I-states represent features of O‑states).  The confusion is that these states mistakenly attribute these features to the same objects, or, in other words, that the states operate as if they are about the same objects.  Apparent diaphanousness results when the internal features represented by I‑states are "projected" onto the external objects represented by O‑states (for instance, cars).  (This does not mean that perceptual experience is wholly illusory--the O‑states may be perfectly accurate about the features of the objects.)  Conversely, we get an illusion of "mental images" when the external features represented by O‑states are misattributed to the internal objects represented by I‑states (namely, O-states).  Understood correctly, apparent diaphanousness, together with apparent images, gives support to an inner perception model of experience--I think there is no other serviceable unified explanation of the illusions, although I can only argue for this elsewhere (Forthcoming).  And the independently plausible binding confusion between outer perception and inner perception satisfies (I) extremely strongly, providing additional reason to believe there is no equivocation in the use of "perceptually appears" as applied to mental states.[37] 

7     A bootstrap 

            What specific phenomenal contributions could inner perception make to experience?  I remain noncommittal about which properties and relations of O‑states are represented by inner perception, but it is worthwhile to explore some possibilities.  Innerly perceptible intrinsic features of an O‑state may include features specific to its hardware realization--such as the rough number of neurons that realize it, or their rough average rates of firing--or more abstract "syntactic" features.  Innerly perceptible relations among O‑states--those that can't be reduced to their intrinsic features--may include certain of their functional relations and perhaps even their spatial relations in the brain.  These are the sorts of properties that we might expect inner‑perceptual processes to detect with some reliability.  Let me illustrate how I take such inner perceptions to enter into perceptual experiences.   

            First, consider cases of double vision or blurred vision.  Typically we are sensitive to the doubleness or blurriness of such experiences.  My suggestion is that this is because we innerly perceive relevant structural or functional properties of our O‑states.  In double vision, we may innerly perceive two O‑states (say, two matching perceptions of an edge) as being two in number (that is, as being distinct).  In blurred vision, we may innerly perceive a certain O-state (say, a perception of an edge) as being in a causal relation with an unusual set of other O-states (say, states that involve neurons unusually and poorly "lined up" in the retinotopic maps in primary visual cortex).  In normal focal vision, by contrast, we are typically sensitive to the nondoubleness and nonblurriness of our experience.  This could be explained by our inner perception of related structural features of O‑states.  We detect an O‑state of an edge as having no distinct matching O‑state, and as being in a causal relation to a standardly "lined-up" set of other O‑states. 

            Or consider a case described by Christopher Peacocke in the course of an argument for the existence of phenomenal properties of experience.  He asks you to consider seeing two same‑sized trees, at varying distances from one along a straight road stretching to the horizon:

Your experience represents these objects as being of the same physical height and other dimensions ....  Yet there is also some sense in which the nearer tree occupies more of your visual field than the more distant tree.  This is as much a feature of your experience itself as is its representing the trees as being the same height.  The experience can possess this feature without your having any concept of the feature or of the visual field: you simply enjoy an experience which has the feature ....  (1983, 12)

Peacocke argues that "you simply enjoy an experience which has the feature" of different sizes‑in‑the‑visual‑field.  However, it is not simply that the experience "has" this visual-field feature, in the way it might "have" the feature of being realized in, say, molecules.  In addition, one is normally sensitive to an experience's visual-field features (in a way one is not normally sensitive to its being realized in molecules).  An inner‑perception account can explain the visual‑field differences in Peacocke's two experiences, as well as one's sensitivity to these features, as follows.  Compared with O‑states about the distant tree, O-states about the nearer tree are realized by (or causally connected to) many more O-states in retinotopic maps in the early visual system.  This is just the sort of relation to which inner perceptions may make one sensitive. 

            All these neural or functional properties allegedly represented by inner perceptions--features we try to describe as "doubleness," "blurriness," "sharpness," "visual‑field size"--are typical examples of qualia, particular aspects of what it is like to have the experiences.  This is indirect support for identifying the qualia of an experience with the contents of inner perceptions.  However, if the best we can do is this indirect support, then even if the inner‑perception account is accepted we invite the charge that we lack a satisfactory explanation of particular qualia, by the extremely demanding standards stipulated by Nagel, Levine, Chalmers, and others.  Even if via the stopgap analysis we can deduce that there is something it is like to have a mental property M, how can we deduce what in particular it is like?  I think the stopgap measures for deducing general phenomenality also provide stopgap measures for deducing particular phenomenal properties, and do so virtually for free.  By the stopgap, it is like something to have M just in case M appears to be some way--via a process that satisfies the specs (A)‑(I), such as inner perception.  So the specific things it is like to have M should be the specific ways M appears to be.  It follows that any two experiences involving inner perceptions with the same content have the same qualia.  This is true not only for comparisons within a subject, but across subjects.[38]   

            Suppose that c's having M involves O-states and I-states as in the previous section, and in this way c's having M is innerly perceived as having some particular property Q.  Then it follows that:
 (10q)   c's having M itself now perceptually appears Q to c‑as‑a‑whole, and this is in order for c to have M.
  (9q)    c's having M itself now perceptually appears Q to c, and this is in order for c to have M.
  (8q)    c's having M itself perceptually appears Q to c.
  (7q)    c's having M has the appearance of being Q for c.
Given the sense of 'is F-like' idiom as explained in the O.E.D. (cf. 'is humanlike,' 'is grim‑like,' 'is like new'), it follows from (7q) that:
  (6q)    c's having M is Q-like for c.
  (5q)    c's having M is like something--Q--for c.
  (4q)    Q is something c's having M is like for c.
And for reasons paralleling those explained in the preliminaries of the stopgap argument, this entails each of the following statements:
  (3q)    Q is something it is like for c, for c to have M.
  (2q)    Q is something it is like for c to have M.
  (1q)    Q is something it is like to have M.
Now, the philosophical jargon of 'qualia' and 'phenomenal properties'--as understood by defenders of the explanatory gap, and by many others besides--is introduced in terms of (or at least in tandem with) statements such as (1q).  A mental state's qualia are what specifically it is like to have the mental state.  If it is like this to have a state, then this is a quale of the state.  So (1q) is equivalent to the more jargon-laden:
   (0q)   c's having M has quale (or phenomenal property) Q. 

            This may give a glimmer of the form of a scientific theory of qualia, but how can a theory specify, much less explain, a particular quale Q?  What is needed is a way to specify the particular contents of inner perceptions.  But this is a general problem in the theory of content, not a specific problem about consciousness and qualia, and it is a problem we can hope to solve.  One semantic dimension is reference--which objects and properties a representation has as its subject matter.  Given a general naturalist theory of reference such as a causal, correlational or teleological one (see the previous section), the trick would be to discover which properties of experiences (in biological creatures, perhaps neural or functional ones) relate in the relevant way with inner perceptions.  Another semantic dimension may be sense (way of representing, mode of presentation), which separates the meanings of coreferential expressions such as '(being) water,' '(being) H20,' and '(being) the liquid that freezes into ice.'  On most naturalist views sense has to do with a representation's relations to other representations or to its representational parts--with its functional role or its syntactic or semantic structure.  Perhaps we can discover which such relations characterize inner perceptions, and perhaps we can isolate other similar semantic dimensions a theory of content may need to posit (if any).  If so, we could objectively specify and explain the particular contents of inner perceptions.  The verdict is still out on whether all this can be achieved, but the key advances are likely to come from thinking about meaning in general rather than qualia and consciousness in particular. 

            The stopgap argument allows conclusions about the existence of phenomenal feels to be deduced from premises solely about nonphenomenal material.  Given a general theory of content, perhaps this can be bootstrapped into a way to deduce conclusions about the essential nature of particular phenomenal feels.  Would anything relevant about conscious experience be left undeduced?  Suppose that we can reach:
   (1)     There is something it is like to have M.
And suppose that for the specific content Q of an inner perception of state M (for the creature as a whole, and so on), we can deduce:
   (1q)   Q is something it is like to have M.
The defender of the explanatory gap may request, in addition to (1q), a derivation of:
   (1t)   This is something it is like to have M,
where 'this' is understood by someone who has M.  In a different context Chalmers, for example, says "we still need to explain why it is like this to be a conscious agent" (1996, 189).  Yet the difference between (1q) and (1t) reveals no gap in scientific explanation. 

            Consider an analogous request as it might be directed elsewhere in science.  Suppose a team of researchers provides a fully satisfying explanation/deduction of:
   (R)    Something is enclosed in fist f.
Also, suppose the research team manages to explain/deduce:
   (Rq)  The specific rock r (with identifying properties R, some of which are tactually perceived by the owner of fist f) is enclosed in fist f.
If I am the owner of fist f, can I reasonably object that the scientists have failed to explain/deduce:
   (Rt)   This is enclosed in fist f,
where 'this' is a demonstrative only I form because only I perceive the rock?  Of course the scientists cannot literally deduce (Rt), since they do not themselves perceive the rock and cannot even form a demonstrative 'this' with the same content (that is, reference and way of referring) that is available to me.  Yet they can be in possession of premises--about the rock, about the content of my perception of it, and about my related formation of 'this'--that logically necessitate the truth of my statement or thought (Rt).  If their premises are true then my assertion or acceptance of (Rt) cannot be false.  Furthermore, they can deduce that my assertion or acceptance of (Rt) is true.  If I learn their premises, I also can deduce that (Rt) is true, and so I can deduce (Rt) itself, given a routine application of a truism I can express as follows: this is enclosed in fist f iff that very statement--'this is enclosed in fist f'--is true.  Only through confusion could I be left wondering why this is enclosed in fist f.  The same points apply to representations of features as well as objects.  Suppose on the basis of perception I represent the shape of the rock, a complex shape I have never noticed before, as follows:
   (St)   Rock r has this shape.
Scientists can be in possession of premises--about the shape of the rock, about my perceptual discrimination of the shape, and about my related formation of 'this shape'--from which they can deduce that (St) is true.  For the same reasons, scientists who can explain/deduce (1) and (1q) can be in possession of premises--about my having M, about the content of my inner perception of it, and about my related formation of 'like this'--from which they can deduce that my statement of (1t) is true.  I also can deduce from their premises that my statements (St) and (1t) are true, and so I have no legitimate room left to wonder why the rock has this shape or why this is something it is like to have M.[39]   

            I end by considering briefly the bearing of this approach on some of the main philosophical claims and controversies about qualia.  This provides a further test of the theory's suitability as a conceptual analysis.  The basic feature to notice is that (10q)--'c's having M itself now perceptually appears Q to c‑as‑a‑whole, and this is in order for c to have M'--does not entail that c's having M actually has (property) Q.  The appearance of Q may be false; in terms of the last section, an I‑state may misrepresent an O‑state as having Q.  An experience can have a quale (or phenomenal property) Q without having (property) Q!  This can only be because talk of "having qualia" and "having phenomenal properties" is peculiarly idiomatic, but this should be no surprise: such talk inherits idiomatic status from the peculiarities of the "what it is like" idiom.  Q can be what an experience is like, even if the experience is not Q, just as new can be what a car is like, even if the car is not new.  A property Q needn't be had by M in order for them to be related by the "is a quale of" relation, just as a property needn't be had by an object in order for them to stand in the "exists at the same time as" or "is as interesting as" relations.  The qualia of an experience are not necessarily properties of the experience, although they are (by a stipulative idiom) necessarily phenomenal properties of the experience.[40]  To be sure, qualia are real properties, with real relations to experiences, even if they are not always properties of experiences.[41]  The property of having quale Q is literally a property of experiences, namely, the property of being represented in certain (for instance, inner‑perceptual) ways as Q.   

            This captures what is true in qualia "realism"--the property Q can exist and bear the "is a quale of" relation to an experience, and can even be had by the experience--while throwing a bone to qualia "eliminativism"--the experience need not have Q.  It gestures similarly to "epiphenomenalism"--if an experience lacks Q it lacks effects in virtue of having Q, but it may nevertheless have effects in virtue of having quale Q.[42]  It also provides what is plausible about a "representationalist" or "intentionalist" theory of qualia--an experience's having quale Q is entirely a matter of what the experience represents (via its component I‑states)--while allowing for the so-called "rival" view that a quale (and the having of it) are "intrinsic" to experience--since the experience represents itself as Q.  It allows for the possibility of "inverted" qualia--two experiences can have the same extrinsic causes and effects, but represent themselves differently--while allowing for the so-called "rival" insight that mental features are "functional" features, matters of what states do--since an experience's particular qualia are matters of what parts of it (O-states) "do" to other parts (I‑states).  A theory that makes sense of so many apparently plausible though apparently conflicting views of qualia has special claim to be an analysis of the concept of qualia shared among the disputants. 

            This approach can even be pressed to explain how a kind of introspection can be complete and infallible with respect to particular phenomenal features or qualia.  If an experience has quale Q, there is an I‑state representing the experience as Q.  If there is an I‑state representing an experience as Q, the experience has quale Q.  The content of inner perceptions constitute which qualia are had, which yields a nonmysterious sense in which introspection of qualia may be infallible and complete.  It does so without implausibly rendering judgments about qualia infallible or complete.  Judgments (or beliefs) about what current experiences are like can easily go wrong.  One can even believe falsely that one is in a state it is like something or other to be in!  If one can have beliefs at all while completely unconscious and lacking qualia--for instance, during dreamless sleep--there would seem to be no reason why one can't mistakenly believe, in such a state, that one is conscious, or has qualia.  Perhaps this explains certain behaviors of hypnotics, sleepwalkers, and sleeptalkers, for instance, those of us who answer the phone while apparently still in a deep sleep, and respond affirmatively when our skeptical caller asks whether we're awake.  Or, if one can have and apply a concept despite being radically confused about its proper application (see Burge 1979), perhaps a blind person can radically misapply a genuine concept of conscious visual experiences, or of qualia, and mistakenly believe he is having visual experiences with particular qualia.  Inner perception can be infallible and complete about qualia even if self‑beliefs about qualia are fallible or incomplete through inattention, breakdown, or other incapacities.[43] 

8     Recap 

            We can deduce the existence of conscious experience from certain scientifically explicable facts.  If one innerly perceives a mental state as being some way, if this inner perception binds with the state, and if this inner perception is centrally available, then it follows, as a matter of conceptual necessity, that there is something it is like for one to have the state.  Given a general theory of semantic content, we can also deduce what in particular it is like to have the mental states.  There is no explanatory gap between nonphenomenal material and phenomenal feels. 




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[1] I mean 'having mental properties' broadly to cover having or being in or undergoing mental states, events, processes, structures, and so on.  I will also sometimes use 'having mental states' in this broad fashion.

[2] Defenders of the gap do of course use many other expressions for what they think is most difficult to explain about experience--'qualia,' 'qualitative properties,' 'phenomenal properties,' 'sensational qualities,' 'raw feels,' and so on.  These are bits of philosopher's jargon, however, and when it comes time to characterize the meaning of these expressions, the weight is almost always shifted to the ordinary phrase 'what it is like.'  (The title of Nagel's 1974 article has had the amount of influence on subsequent work that marks many a respectable career.)  From time to time this is supplemented by appeal to allegedly troublesome features of "qualia": subjectivity, direct and/or infallible and/or complete introspectibility, ineffability, unanalyzability, intrinsicality, epiphenomenality, and so on.  While I begin (as gap‑defenders do) with focus on 'something it is like,' a relevant test of my conclusions would be the extent to which they explain why experience involves or at least seems to involve such features.  I also consider the philosophical jargon itself in note 40.

[3] Perhaps the cumbersome 'there is something it is now like to have M, and this is in order to have M' would do.

[4] One possible role of the 'for' in (2) mirrors that of the 'to' in (1), expressing an in‑order‑for.  We can favor this reading merely by emphasizing 'for' in (2)--'it is like something FOR c to have M'--or by reversing the order of the phrases in (2)--'for c to have M, there is something it is like.'

[5] See note 26 for a suggestion about how these two readings can diverge in truth value.

[6] When called upon to specify 'is like something,' defenders of the gap often use 'is like this' and its comrade 'is like that.'  While this may seem to violate (a), the problem remains, since the reference is to this or that way rather than to this or that thing.

[7] From works between 1500 and 1801 the O.E.D. lists "[y]on man is lyke out of his mynd," "[a]ll looking on and like astonisht staring," "... seems like dead," and "[b]eing his tenant, he was like in his power" (Like, adv., B.3.a., L‑285).

[8] From works between 1470 and 1724 the O.E.D. lists "quietlik," "triumphaunt lyke," "[of] countenance English like," "innocent like," "Venerable like," "inconsiderate like," "[a] man ... auld like and bauld like," and so on (-like, suffix, 2.a., L‑287).

[9] Or as in my personal favorite from the O.E.D.'s modern Scotch selection: "Dinna rug at it sae rochlike [= roughly], or ye'll brak it" (-like, suffix, 2.b, L‑287).

[10] For purists who may insist that 'F‑like' should stand for an adverb (akin to 'F-ly') rather than for an adjective as in (6), an equivalent alternative would be:
   (6a)   For some F, c's having M exists F-like (F-ly) for c.
According to the O.E.D., this adverbial use is obsolete "exc[ept] in Sc[otch], where the sense of the adv[erbs] is rather 'so as to appear --'" (-like, suffix, 2.b, L‑287), which renders (6a) as:
   (7a)   For some F, c's having M exists so as to appear F for c.
This is equivalent to (7).

[11] The possible suggestion that the use of 'F‑like' in (6) is wholly sui generis should be credible only as a last resort, only if there is clear reason to think all interpretations based on comparison classes fail.  Much of the rest of this article is an attempt to argue that there is no clear reason to think the use of the O.E.D.'s definition fails.

[12] Many uses of 'for' cannot be followed by a term for a creature at all.  Of those that can, some are clearly irrelevant--for instance, substitution ('you for me'), support ('vote for me')--while others are nearer misses--for instance, purpose or destination ('made for me'), advantage or disadvantage ('good for me').

[13] Of course, 'sight' should be taken broadly, as should 'feels' in the following paragraph.  And 'in the presence of' should mean not simply 'positioned near' but 'positioned to be seen by,' since the pain in my leg is positioned near my leg and my medicine cabinet (as opposed to Mars), but is not positioned to be seen by them. 

[14] The irresistible practice of specifying 'something' with demonstratives ('this,' 'that'), as in note 6, is further evidence that 'appears' needs to be construed perceptually (rather than merely as involving disposition to judgment).  A perceptual sensitivity to something typically enables one to identify it demonstratively.  A nonperceptual (disposition to) judgment about something typically enables one to identify it descriptively.

[15] If anyone is left wondering why bananas (and other material objects) lack phenomenal properties, given that they appear some way, an initial answer is that these appearings are not necessary for bananas to exist.  (All bets are off if idealism is true--maybe then bananas do have phenomenal properties.)  In note 37 I describe a fuller answer.

[16] As throughout, c is some particular creature with mental property M.  This may generate some hesitation about whether (2) entails (1), if (1) is read as 'there is something it is like for any creature to have M.'  I did not introduce (1) as a general claim, but as a claim about some creature c's having M.  Perhaps there are types of mental states that are qualitative for some creatures but not for others.  To reach a more general claim about any creature's possession of M, one could substitute for 'c' in (2)‑(10) a variable 'x' ranging over creatures, and bind this variable with a 'for all x.'  The stopgap argument would remain the same in all other respects.

[17] In pursuing this strategy I do not claim that deduction from scientific laws is sufficient for explanation, as in the deductive‑nomological model (for a gap‑defender's gesture towards this model, see Levine, 1994, 129-130).  There are many well‑known reasons for thinking deduction from laws is too weak to explain explanation, but these seem irrelevant to the present case.  For example, explanation is typically asymmetric in a way that deduction from laws does not reflect: if we can deduce an effect E from a cause C and the law L, we can also deduce notC from the premise not‑E and the law L.  But typically C (with L) explains E, while not‑E does not explain not‑C.  Such asymmetries are not threats to the deductive explanation I will give.  I assume there would be no serious temptation to argue, even if the stopgap deductions hold, that the proper direction of explanation is from the presence or absence of something it is like to the presence or absence of the neural or psychological facts I will use to explain (A)‑(H).  Each of these facts can hold in the absence of something it is like, each can be tested independently in ways familiar to the sciences, and so on.

[18] It is no help to expand (5a) to take into account the overarching requirements (α) and (β), since the following is equally trivial: 'c's having M is now similar to something, and this is in order for c to have M.'

[19] Perhaps this is because it is not necessary that I believe these states are similar to something, in order for me to have them?  This requirement is easily met by switching examples, say, from a Freudian hatred to a Freudian hatred that I believe similar to other Freudian hatreds.  It is necessary for having the latter state, even if not the former state, that I believe my having it is similar to something.  Still, there seems to be nothing it is like for me to have the latter state itself, especially if the only reason I believe in the state is because I read Freud and hazard guesses about my unconscious mind. 

[20] I do not think the relevant requirement is that the perceptible features should be intrinsic to the car--color counts, for instance, but it may not be intrinsic--but they should be features one can perceive largely in perceiving (parts of) the car rather than other things.  Perhaps a car could be like new and in Emerald City, where everything appears green.

[21] Even without this extremely plausible assumption, for (5i) to be true c's having M must appear to have the feature of being similar to something, and again (5i) entails (8).

[22] Even without this extremely plausible assumption, for (8) to be true c's having M must appear similar to itself, and therefore to some thing, and again (9) entails (5i).  Presumably this would be false only for creatures radically simpler than human beings and most other animals, creatures somehow utterly unable to detect similarity at all.  If such creatures can have conscious experiences, (5i) is too strong to be a good interpretation of (5), and so it is not a plausible rival to (6)‑(10).  If such creatures cannot have conscious experiences, then (5i) may be a good interpretation of (5).  But then (8) would fail to entail (5i) only for creatures that have extremely primitive representational powers and are incapable of conscious experiences.  In that case (8)‑(10) could still specify what it is for a creature capable of conscious experiences to have them.

[23] The intuitive distinction between perception and (disposition to) judgment is vexed, to say the least.  What matters to the present argument is simply that I avoid equivocating, by explaining 'appear' in the same sense that explains 'is F-like' (in the general range of cases).  If (contrary to what I suspect) this kind of "appearing" deserves the name of "perceptual judgment," that is fine with me.  In that case, the focus would be on the features that distinguish perceptual judgment from nonperceptual judgment.  Even if we were to use the same term ('judgments') for narrowly perceptual states and highly conceptual, descriptive, or theoretical states, there are enough practically important and commonsensically apparent differences to make it likely that two ordinary concepts are involved.  I describe some of these differences in section 6 below.

[24] In subliminal perception and blindsight subjects come to represent things by looking, despite denying--sincerely, and without hypochondria--that they have relevant visual experiences (see Weiskrantz, 1988).  The claim that some such states do lack phenomenal properties is typically granted by defenders of the explanatory gap, and is typically exploited by them in order to focus attention, by contrast, on what is distinctive about conscious experience.  I am content to rest on this agreement; I believe the claim is plausible on its own, although it is of course controversial in some circles.  Perhaps a fuller argument for it would show that these states lack the allegedly troublesome second‑order features associated with phenomenal properties (see note 2).  These states do not involve mental features that even seem (rightly or wrongly) to be directly or reliably introspectible, private, ineffable, unanalyzable, intrinsic, irreducible to functional or representational relations, or mysterious in function.

[25] In summing up his objection to Dennett, Chalmers reflects:

In general, 'seeming' is a poor term to use in characterizing the explananda of a theory of consciousness, ....  It is interesting that it is usually used only by proponents of reductive accounts.  (1996, 380)

But in fact the ubiquitous appeal of gap‑theorists to 'what it is like' is a covert appeal to (inner) seeming--not in Chalmers weak (alleged) "psychological" sense or his strong (alleged) "phenomenal" sense, but in the ordinary "perceptual" sense I employ.

[26] Perhaps innerly blindseen states would be like something for some part or subsystem of a creature, or perhaps they would be like something for the creature in some loose sense.  I am not crucially concerned here with such unclear cases of phenomenality, but this suggestion has some attractions.  It would allow for multiple centers of phenomenality in, say, split‑brain cases--when few if any states are clearly for the whole person.  It would also allow for phenomenality in cases of "hysterical blindness," apparently normal vision coupled with complaints of blindness (see Dennett, 1991, 327).  In such cases, it is unclear that there is central or global availability--the subjects seem to lack higher‑order belief in experiences, to lack the ability to report on what they perceive, to lack spontaneity and self-confidence, and so on.  (The vision is "apparently normal" because there is no gross damage to visual (or other) areas, and because, as Dennett describes, such subjects "have an uncanny knack of finding chairs to bump into."  Yet this is a psychiatric disorder in which the subjects seem genuinely to be mistaken about themselves, and not simply to be lying about themselves.)  Finally, the suggestion allows for phenomenality in animals and babies that lack reportability and beliefs about experiences.  Perceptual states of animals and babies do provide spontaneity, and global control in a sense (although their "globe" is relatively small).  They lack explicit self‑confidence but perhaps have tacit self‑confidence.  Of course, it might be that animals and babies lack qualia, and it might even be that brain‑splitting or blindness‑hysteria "turn off" qualia.  Equally, there may or may not be inner perception in these cases.  At this stage of knowledge, these cases are far too unclear to carry theoretical weight.

[27] Michael Tye agrees that superblindsight states are not phenomenal, but argues that this is because they are not "directly" available for influencing cognition and conation:

[The] representations pertinent to the blind[sight] field that are available to serve as inputs to the conceptual domain have an effect on the beliefs of super‑blindsight subjects only via their willing themselves to guess.  Without such acts of will, there would not be any beliefs about the contents of the blind[sight] field.  So the impact on the belief system here is both anomalous and indirect.  First, an act of will is required; then a guess is generated; then the guess comes to be believed.  (Tye, 1995, 143)

Many other philosophers emphasize the requirement of direct global control (Kirk, 1994, 142ff.; Dretske, 1995, 20; Chalmers, 1996, 222).

            I am skeptical about the relevance of directness for phenomenality.  Start with a normal Earthling replete with phenomenality, whose sensory neural systems bring about beliefs in his central system via normal neural channels.  Next, unbeknownst to him, reroute these sensory signals to the same belief destinations, via switchboard operators far away.  What difference would this indirectness make to what the states are like?  None, I think.  Nor would it help to define "direct" influence as influence unmediated by factors that one believes in (cf., in a different context, Rosenthal, 1990), since the subject could be told about the switchboard without robbing him of phenomenality.  (I think he could even help operate the switchboard, without affecting the counterexample.)

            The difference Tye emphasizes between "guesses" and "beliefs" is also of dubious relevance.  There is a fine line, if any at all, between a guess that p and a weak belief that p, or a strong belief that maybe p.  What Tye calls "guesses" might as well be called "hypotheses"--and on many theories of normal perceptual‑belief fixation, hypotheses are first generated, then through competition some come to be believed.  As for the role of "willing" in superblindsight, this does not seem essential to the case.  Perhaps with enough practice the willed guesses become routine and automatized, like skills generally.

            Finally, unlike an inner‑perception requirement, there seems to be no conceptual motivation for a directness requirement in explaining what it is like for a creature to have a mental state.

            Kirk, on the other hand, tries to argue as follows that outer‑perceptual states that are for a creature have "character" for the creature:

There is no mystery about how such differences in character (for the system) could exist.  They consist in different patterns of activation of various complexes of units in the system ... which have different effects on the processes of assessment, decision‑making, and action initiation.  (1994, 147)

I believe a sheer (innerly unperceived) difference in "patterns of activation" is insufficient for phenomenal character, even for states that are "for the system."  Beliefs and other central propositional attitudes are for the system, and are (presumably) realized in varying patterns of activation, but are nonphenomenal.

[28] See also Block's (1995) distinction between the concepts of access consciousness (roughly, availability for central rational influence) and phenomenal consciousness.

[29] As mentioned in section 2, the "as a whole" requirement must be loose or vague, which renders the distinction between nonphenomenal and phenomenal perception vague.  I believe this is independently plausible, commonsensically.  There seem to be fuzzy boundaries at the edges of one's visual field, for example, and intuitively it is hard to tell exactly when there becomes something it is like to see a peripherally moving object.  Similarly, when one's attention is drawn to various faint pressure sensations or itches around one's body, it can be hard to answer whether there was something they were like a moment earlier.  Daniel Dennett argues in other ways that the conscious/nonconscious distinction is vague, and uses this against inner‑perception theories.  But as I respond elsewhere (1994) it is independently plausible that inner perception is vague--there is vagueness in the distinction between mere reflexive reactions to stimuli and (even unconscious) representings of stimuli, for example.

            Perhaps this is to jump out of the frying pan and into the fire, however, if the following argument of Chalmers' is correct:

Either there is something it is like to be a mouse or there is not, and it is not up to us to define the mouse's experience into or out of existence.  To be sure, there is probably a continuum of conscious experience from the very faint to the very rich; but if something has conscious experience, however faint, we cannot stipulate it away.  This determinacy could not be derived from any functional analysis of the concepts in the vicinity of consciousness, as the functional concepts in the vicinity are all somewhat vague.  If so, it follows that the notion of consciousness cannot be functionally analyzed.  (1996, 105)

We need to distinguish two respects in which conscious experience can be "faint": what is had can be faint, or the having of it can be faint.  Chalmers' claim is plausible on the first reading--even if there is something‑faint it is like to be a mouse, there is something it is like to be a mouse.  But perhaps instead there faintly‑is (that is, indeterminately is) something it is like to be a mouse, in which case it would neither be true nor false that there is something it is like to be a mouse.  The possibility of indeterminately-having qualia is opened up by the vagueness of "as a whole," and by the possibility that a state may neither be determinately an inner perception nor determinately a mere inner reflex reaction, but somewhere in the vague between.

[30] It is certainly possible for a state to represent itself somehow, but understandable kinds of reflexive representation are not phenomenally relevant; arguably, one can have a wholly nonphenomenal belief that all beliefs are mental, a wholly nonphenomenal intention that one's arm rise as a result of this very intention (see Searle, 1983, 85), and so on.

[31] There are several points of difference between (outer) perceptual states and judgments, which might be appealed to in distinguishing inner perception from inner judgment (although the terminology is fluid--see note 23).  The clearest cases of nonperceptual judgments have large degrees of five "freedoms" that strictly perceptual states lack (for related arguments, see Fodor, 1983):

   (1)     Freedom from stimuli--Judgments have a strong ability to persist in the face of apparently disconfirming stimuli, familiar perceptual illusions, fictional pretenses (for instance, movies), and so on. 

   (2)     Freedom from behavioral consequences--Judgments have a strong ability to persist without influencing action, since their systematic influences on action are only via practical inferences with independent desires.  Perceptual states characteristically help to control behavior, especially perceptual‑motor skills, even in the absence of the kinds of goals, plans, and desires that cooperate with (nonperceptual) judgments.

   (3)     Freedom of inferential assembly--A judgment is able to be used as a premise for or a conclusion of a wide range of other judgments, given suitable auxiliary judgments.  One of the reasons that perceptual states have relatively rigid connections to stimuli is that there are relatively rigid restrictions on the "premises" that can be used in forming perceptual states.

   (4)     Freedom of semantic assembly--Judgments are able to involve a wide range of one's ideas (concepts, percepts) largely independently of domain, in a wide range of one's available semantic structures (for instance, logical forms).  For most of the states involved in perceptual processing, by contrast, a fair rule-of-thumb is that they represent a property F only if F (or perhaps some contrary of F) is relevant to biological needs and perceptual‑motor skills, and is reliably detectable in a wide variety of natural contexts.  There also seem to be limitations on the ability to perceive (e.g.) disjunctive, negative, and conditional facts involving these properties.

   (5)     Free-range contents--Judgments are able to share contents with a wide range of other attitudes and processes, for instance, desiring, pretending, hypothesizing, remembering, and expressing in public language.  Several perceptual states (conscious or unconscious) have contents that cannot be matched by desires, emotions, pretenses, hypotheses, recallings, communication-intentions, and so on.

I think the relevant sense of 'appear' in the stopgap argument, the one ordinarily relevant to 'is F-like,' applies to states that lack (large degrees of many of) these freedoms.  We should expect inner perceptions to generate judgment‑resistant illusions, to guide motor skills, to be formed on the basis of a limited range of premises, to involve a limited range of ideas, and to be difficult to remember and express in public language.

[32] There is perhaps a sense of 'perception' in which it requires the operation of sense organs.  But even in this sense inner perception is introspectively practically indistinguishable from outer perception.  Even when we close our eyelids, we seem to use our eyes to "see" the resulting fireworks that seem to display on the back of our eyelids.  And even in cases in which we speak of "seeing" mental images with our "mind's eye," we naturally move our body's eyes as we "scan the images," just as if we were scanning pictures.

[33] I do not assume (or deny) that I-states involve complex descriptive concepts of neural structure or of psychological function; another possibility is that they respond to specific neural or psychological features in more primitive ways, just as in outer perception one may be sensitive to wavelengths or molecular motion without having concepts of waves or molecules.  In the next section I give some illustrations of particular innerly perceptible properties and how they would explain the particular qualia of experience.

            Even if I‑states do not involve highly complex concepts of features of O‑states, they need not be restricted to nonconceptual content in any sense akin to that of Evans (1982).  I‑states may involve relatively simple concepts of O‑state features, concepts enabling one to remember the features, to imagine them, to think of novel combinations of them, and otherwise to satisfy Evans' "generality constraint." 

[34] This assumption coheres with psychophysical claims about the contents of many states of perceptual systems.

[35] Partisans of bolder reflexivity theories may simply think of the inner‑perception arrow as looping back to its source, affecting what content the source has.

[36] A state consisting of all but the rightmost element, the connection between an I‑state and central systems, would perhaps be phenomenal (that is, like something) but not phenomenal for the creature (see note 266).

[37] Furthermore, the confusion between O‑states and I‑states grounds the idea that they are "unified" in a psychologically natural larger state (a conscious experience).  This unification provides an additional reason to deny that bananas (and other material objects) are phenomenally conscious, even though they appear some way (see note 15).  When I-states and O-states interact, phenomenal illusions are created--"image illusions" of phenomenal objects in one's mind (mental images subjectively having environmental features--for instance, color and shape), or "transparency illusions" of phenomenal properties in one's environment (environmental objects objectively having mental features--for instance, varying "looks" versus "feels" of a constant shape).  I argue elsewhere (Forthcoming) that, at least in the clearest cases, these illusions are present in all and only phenomenal experiences--in perception, bodily sensation, imagination, and thought.  But no such illusions are generated when O‑states and bananas interact (without I‑states).  They only occur when O‑states and I-states interact (with or without bananas). 

[38] In particular it remains true in comparing states that are like something for a creature as a whole and states that are like something but not for a creature as a whole.  If inner blindsight yields phenomenal properties at all (see note 26), it yields the same phenomenal properties as centrally available inner perception, though not for the same "subject."  It is like the same "thing" to be in states that differ only in connections to central systems--states that differ only in the rightmost arrow in the diagram of the previous section (see note 36).  This allows, however, that central systems may generate further experiences that are absent in inner blindsight--such as auditory experiences "labeling" visual experiences--or may feed back into visual systems and alter the inner perceptions there.

[39] Of course, the scientists need not have experiences with the quale Q in order to explain (specify, conceive of) experiences with the quale Q.  This distinction is clear in the case of most subject matters: one can fully explain a rock without having a rock.  But confusion is more tempting when the subject matter is representation itself: how can one fully explain a subject's way of representing qualia without having that way?  Nevertheless, in general one can explain the particular ways of representing involved in unavailable representational states, even by reference to their essential properties.

            Consider belief contents as an analogy.  Perhaps we cannot have a belief with the same content (that is, with the same reference and way of referring) as Napoleon's belief that he was the emperor of France.  But so long as we can isolate the dimensions along which ways of referring to things vary, we can objectively specify and explain Napoleon's way of referring to himself--for instance, as using the "simple first‑person singular demonstrative concept that refers to Napoleon" rather than a concept that is complex, third‑person, plural, descriptive, about Josephine, and so on.  Even though we don't have such a concept of Napoleon, we've fully specified it if there can be only one such concept.  If so (give or take some tinkering), we can specify and explain Napoleon's belief objectively, via its essential properties: it is a belief by Napoleon predicating French‑emperorhood of Napoleon using Napoleon's first‑person concept.

            The point is not restricted to demonstratives or indexicals.  We (human beings) have fairly primitive, perceptually‑based concepts of being warm and of being in motion.  But consider a concept‑using being with different sensory capabilities, a being able perceptually to distinguish warm, moving objects from other things, but unable perceptually to distinguish warm objects as a class or to distinguish moving objects as a class.  Such a being may form a fairly primitive concept true of all and only warm, moving things, even though it is not structured out of concepts of being warm and of being in motion.  This is a concept we (human beings) may be unable to share; perhaps the closest we can come is our conjunctively complex concept of being warm and in motion.  But this need not prevent us from specifying and explaining the unavailable concept's reference (warm, moving things), its semantic structure (the concepts it is structured out of, if any), and perhaps other dimensions of content.

            Similarly, even if a subject has a special inner‑perceptual way of representing a mental state that is unavailable to scientists, the scientists can in principle specify and explain this specific way of representing, in other ways.

[40] 'Phenomenal properties' is to 'properties' much as 'decoy duck' is to 'duck,' at least if we allow that one can--but needn't--use a duck as a decoy duck.  The parallel with 'apparent duck' is more exact.  This is one of many indications that the stopgap argument's invocation of inner perception is not a mere fluke made possible by the single idiom 'what it is like.'  'Phenomenal' in 'phenomenal properties' suggests "(perceptually) apparent" as it has for philosophers from Kant to 20th‑century phenomenologists to analytic phenomenalists.  Talk of "feels" also suggests inner perception, a suggestion reinforced by the phrase 'raw feels,' which suggests that the inner access is "perceptual" in some sense that might be opposed to "conceptual," "descriptive," or "theoretical."  "Subjective qualities" suggests qualities for which to be (instantiated) is to be perceived (to be instantiated), and if these are to be "qualia" possessed by experiences, the relevant perception should be inner perception.  The etymologically‑based connotations of 'introspection'--historically the most important notion of consciousness--are obvious.  (However, I do not offer inner perception as a complete account of introspective consciousness; there are additional processes of introspection.)  Even the core meaning of the term 'conscious' itself, as applied to mental states such as experiences, is plausibly to describe states of which one is conscious, states of which one has a special inner source of knowledge.  I discuss historical uses of such terms more fully elsewhere (1998).

[41] The possibility of inner misperception of Q-ness need not raise any special mystery about the kind of property Q is nor about how it comes to be inwardly represented.  (Thanks to an anonymous referee for requesting clarification here.)  I suggested and illustrated above that innerly perceived properties might be ordinary intrinsic or causal features discoverable by neurology or psychology.  Even if a particular experience is inwardly misperceived as having Q, Q could be an ordinary neural or causal property instantiated on occasion by other experiences or nonexperiential brain states. And even if Q is never instantiated by any actual experience or brain state, Q could be a complex of individually instantiated neural or causal properties, or a determinant property falling under the same neural or causal determinable as some alternative instantiated determinants. On any of these possibilities, Q would be available to be represented according to more or less sophisticated naturalistic theories of representation.

[42] One empirical objection to inner perception that I have not addressed is: why would we have it--for what function?  I think this is a difficult question to answer, as questions about the driving forces of and constraints upon evolutionary design sometimes are.  One can speculate, of course.  Perhaps among other things it gives us a way to detect deficiencies in our perceivings (lack of focus, doubling, obscuring relations among objects, and so on).  Or perhaps our inner perceptions are remnants of a primordial ancestry before reliable distal (outer) perception developed, when representations of one's internal organs were the next best thing.  In any case what I would urge now is that the same mystery about function arises about phenomenality and qualia: why do we have them?  The objection against inner perception could be a selling point for it as an account of phenomenality and qualia!  Given how difficult it is to understand what functions qualia play, if any, it would be surprising if an analysis of 'what it is like' resulted in a phenomenon with obvious functions.

[43] Since gap‑theorists sometimes believe nonphenomenal zombies are possible, they would do well to have an account of how we know we are not such zombies.  In an interesting discussion, Chalmers registers the following views:

To have an experience is automatically to stand in some sort of intimate epistemic relation to the experience--a relation that we might call 'acquaintance.'  There is not even a conceptual possibility that a subject could have a red experience like this one without having any epistemic contact with it: to have the experience is to be related to it in this way.  (1996, 197)

Music to my ears.  Even better, he emphasizes that this epistemic contact cannot plausibly be understood via self-beliefs:

[W]e have many experiences that we do not have beliefs about, and so do not know about.  Further, one might have an experience without conceptualizing the experience in any way.  To have an experience, and consequently to be acquainted with the experience, is to stand in a relationship to it more primitive than belief: it provides evidence for our beliefs, but it does not in itself constitute belief.  (1996, 197)

Yet he closes his discussion with the admission that "many issues remain to be dealt with ... [i]n particular, one would like an analysis of just how an experience justifies a belief" (1996, 199).  I offer Chalmers the "analysis" that experiences justify our occasional beliefs about them via our "more primitive" inner perceptions of them, just as rocks justify our occasional beliefs about them via perceptions of them.  Since experiences (unlike rocks) contain the inner perceptions, "there is not even a conceptual possibility that a subject could have a red experience like this one" without innerly perceiving it to be this way (that is, the way this one is).  The only price I ask is the admission that, conversely, there is not even a conceptual possibility that a subject could innerly perceive a state to be this way, without having an experience like this one.  I will grant that "to have the experience is to be related to it in this way" if it is granted in return that to be related to a state in this way is to have an experience.  The price of nonmagical complete and infallible "acquaintance" to experience is that experience is constituted by this nonmagical acquaintance.  This is a "price" we have to pay anyway, on a proper analysis of the 'what it is like' idiom, and associated talk of 'having qualia' and 'having phenomenal properties.'