Forthcoming 2005 in Philosophical Review
(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
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.
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:
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:
Chalmers characterizes the problem most fundamentally in the same 'something it is like' way, then adds more jargon‑laden characterizations:
Why is it so hard, according to Chalmers? For exactly the reasons specified by Nagel and Levine:
Helpfully, Chalmers hones the challenge as follows:
Okay, then: I choose
both "truth" and "dare." I will try to give defenders of the
explanatory gap exactly what they say they want.
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
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. 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
strikes the right conceptual chord in so many people:
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:
'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):
'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.):
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):
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. 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:
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,
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.' 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):
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,
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
'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). 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. 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.
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
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,
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:
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):
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
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):
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) 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:
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:
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
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):
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):
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. (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:
Further difficulties arise from the widespread philosophical stipulation
mentioned in the previous section:
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):
If an "is similar to" reading has any remaining plausibility, I think this is
because we so easily construe similarity specifically as
similarity--a construal that is even easier for 'resembles'--as in the following
potential interpretations of (5):
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:
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:
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
of experience--while I wish to explain how
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":
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:
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:
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').
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, present‑tensedness,
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. (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
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):
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.
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. This does not mean that I am explaining
normal phenomenal perception as simply
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.
Blindsight subjects have portions of their visual field--"blindsight
regions"--in which they deny that they have conscious experiences of specific
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
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":
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.
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
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
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
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. 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.
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
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?
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.
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
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,
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.
They may qualify as perceptual due to their use, even if not due to their
(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
(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).
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
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.
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.
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,
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
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
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.
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
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
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:
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
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.
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
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:
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
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.
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:
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:
Consider an analogous request as it might be directed elsewhere in science.
Suppose a team of researchers provides a fully satisfying
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)
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
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.
To be sure, qualia are real properties, with real relations to experiences, even if they are not
always properties of experiences. 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
it lacks effects in virtue of having Q,
but it may nevertheless have effects in virtue of having quale Q. 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
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.
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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 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.
 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.
 Perhaps the cumbersome 'there is something it is now like to have M, and this is in order to have M' would do.
 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.'
 See note 26 for a suggestion about how these two readings can diverge in truth value.
 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.
 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).
 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).
 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).
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:
 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.
 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').
 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.
 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.
 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.
 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.
 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 not‑C 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.
 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.'
 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.
 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.
 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).
 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.
 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.
 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.
 In summing up his objection to Dennett, Chalmers reflects:
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.
 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.
 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:
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:
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.
 See also Block's (1995) distinction between the concepts of access consciousness (roughly, availability for central rational influence) and phenomenal consciousness.
 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:
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.
 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.
 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.
 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.
 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."
 This assumption coheres with psychophysical claims about the contents of many states of perceptual systems.
 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.
 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).
 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).
 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.
 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.
 '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).
 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.
 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.
 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:
Music to my ears. Even better, he emphasizes that this epistemic contact cannot plausibly be understood via self-beliefs:
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.'