Feelings
and experiences vary widely. For example, I run my fingers over sandpaper,
smell a skunk, feel a sharp pain in my finger, seem to see bright purple,
become extremely angry. In each of these cases, I am the subject of a mental state
with a very distinctive subjective character. There is something it is like
for me to undergo each state, some phenomenology that it has. Philosophers
often use the term ‘qualia’ (singular ‘quale’) to refer to the introspectively
accessible, phenomenal aspects of our mental lives. In this standard, broad
sense of the term, it is difficult to deny that there are qualia. Disagreement
typically centers on which mental states have qualia, whether qualia are
intrinsic qualities of their bearers, and how qualia relate to the physical
world both inside and outside the head. The status of qualia is hotly debated
in philosophy largely because it is central to a proper understanding of the
nature of consciousness. Qualia are at the very heart of the mind-body problem.
The entry that follows is
divided into eight sections. The first comments on other more restricted uses
of the term ‘qualia’. The second addresses the question of which mental states
have qualia. The third section brings out some of the main arguments for the
view that qualia are irreducible and non-physical. The remaining sections focus
on functionalism and qualia, the explanatory gap, qualia and introspection,
representational theories of qualia, and finally the issue of qualia and simple
minds.
Consider a
painting of a dalmatian. Viewers of the painting can apprehend not only its
content (i.e., its representing a dalmatian) but also the colors, shapes, and
spatial relations obtaining among blobs of paint partly by virtue of which it
has that content. It has sometimes been supposed that being aware or conscious
of a visual experience is like viewing an inner, non-physical picture or
sense-datum. So, for example, on this conception, if I see a dalmatian, I am
subject to a mental picture-like representation of a dalmatian (a sense-datum),
introspection of which reveals to me both its content and its intrinsic,
non-intentional features partly by virtue of which it has that content. These
intrinsic, non-intentional features have been taken by advocates of the
sense-datum theory to be the sole determinants of what it is like for me to
have the experience. In a second, more restricted sense of the term ‘qualia’,
then, qualia are intrinsic, consciously accessible, non-intentional features of
sense-data and other non-physical phenomenal objects that are responsible for
their phenomenal character.
With the demise of the
sense-datum theory, there are very few philosophers who believe that there are
qualia, so conceived. Still, there is another established sense of the term
‘qualia’, which is similar to the one just given but which does not demand of
qualia advocates that they endorse the now discredited sense-datum theory. However
sensory experiences are ultimately analyzed -- whether, for example, they are
taken to involve relations to sensory objects or they are identified with
neural events or they are held to be physically irreducible events -- many
philosophers suppose that they have intrinsic, consciously accessible features
that are neither intentional nor intentionally determined and that are solely
responsible for their phenomenal character. These features, whatever their
ultimate nature, physical or non-physical, are often dubbed ‘qualia’.
In the case of visual
experiences, for example, it is frequently supposed that there is a range of
visual qualia, where these are taken to be intrinsic features that (a) are
accessible to introspection, (b) can vary without any variation in the
intentional contents of the experiences, (c) are mental counterparts to some
directly visible properties of objects (e.g., color), and (d) are the sole
determinants of the phenomenal character of the experiences. Philosophers who
hold or have held this view include, for example, Nagel (1974), Peacocke (1983)
and Block (1990).
Philosophers who deny that
there are qualia often have in mind qualia, as the term is used in the senses
specified in this section. Sometimes their target is qualia, conceived of as in
the opening paragraph of the entry, but with the additional assumption (often
not explicitly stated) that qualia are ineffable or nonphysical or ‘given’ to
their subjects incorrigibly (without the possibility of error). Thus,
announcements by philosophers who declare themselves opposed to qualia (e.g.,
Dennett 1987, 1991) need to be treated with some caution. One can agree that
there are no qualia in the more restricted senses I have explained, and also
agree that there are no ineffable or incorrigibly presented or non-physical
qualities possessed by our mental states, while still endorsing qualia, in the
standard broad sense.
In the rest of this entry,
I shall use the term ‘qualia’ in the standard, broad way I did at the beginning
of the entry. So, I shall take it for granted that there are qualia.
The
following would certainly be included on my own list. (1) Perceptual
experiences, for example, experiences of the sort involved in seeing green,
hearing loud trumpets, tasting liquorice, smelling the sea air, handling a
piece of fur. (2) Bodily sensations, for example, feeling a twinge of pain,
feeling an itch, feeling hungry, having a stomach ache, feeling hot, feeling
dizzy. Think here also of experiences such as those present during orgasm or
while running flat-out. (3) Felt reactions or passions or emotions, for
example, feeling delight, lust, fear, love, feeling grief, jealousy, regret. (4)
Felt moods, for example, feeling elated, depressed, calm, bored, tense,
miserable. (For more here, see Haugeland 1985, pp. 230-235).
Should we include any other
mental states on the list? Galen Strawson has recently claimed (1994) that
there are such things as the experience of understanding a sentence, the
experience of suddenly thinking of something, of suddenly remembering
something, and so on. Moreover, in his view, experiences of these sorts are not
reducible to associated sensory experiences and/or images. Strawson's position
here seems to be that thought-experience is a distinctive experience in its own
right. He says, for example: "Each sensory modality is an experiential
modality, and thought experience (in which understanding-experience may be
included) is an experiential modality to be reckoned alongside the other
experiential modalities" (p. 196). On Strawson's view, then, some thoughts
have qualia.
This view is controversial.
One response is to claim that the phenomenal aspects of understanding derive
largely from linguistic (or verbal) images, which have the phonological and
syntactic structure of items in the subject's native language. These images
frequently even come complete with details of stress and intonation. As we
read, it is sometimes phenomenally as if we are speaking to ourselves. (Likewise
when we consciously think about something without reading). We often
"hear" an inner voice. Depending upon the content of the passage, we
may also undergo a variety of emotions and feelings. We may feel tense, bored,
excited, uneasy, angry. Once all these reactions are removed, together
with the images of an inner voice and the visual sensations produced by
reading, some would say (myself included) that no phenomenology remains.
In any event, images and
sensations of the above sorts are not always present in thought. They are not essential
to thought. Consider, for example, the thoughts involved in everyday visual
recognition (or the thoughts of creatures without a natural language). Consider
also deeply unconscious thoughts. So, certainly some thoughts lack qualia.
What about desires, for
example, my desire for a week's holiday in Venice? It is certainly true that in
some cases, there is an associated phenomenal character. Often when we strongly
desire something, we experience a feeling of being "pulled" or
"tugged". There may also be accompanying images in various
modalities.
Should we include such
propositional attitudes as feeling angry that the house has been burgled
or seeing that the computer is missing on the list? These seem best
treated as hybrid or complex states, one component of which is essentially a
phenomenal state and the other (a judgment or belief) is not. Thus, in both
cases, there is a constituent experience that is the real bearer of the
relevant quale or qualia.
The
literature on qualia is filled with thought-experiments of one sort or another.
Perhaps the most famous of these is the case of Mary, the brilliant color
scientist. Mary, so the story goes (Jackson 1982), is imprisoned in a black and
white room. Never having been permitted to leave it, she acquires information
about the world outside from the black and white books her captors have made
available to her, from the black and white television sets attached to external
cameras, and from the black and white monitor screens hooked up to banks of
computers. As time passes, Mary acquires more and more information about the
physical aspects of color and color vision. (For a real life case of a visual
scientist (Knut Nordby) who is an achromotope, see Sacks 1996, Chapter 1.) Eventually,
Mary becomes the world's leading authority on these matters. Indeed she comes
to know all the physical facts pertinent to everyday colors and color
vision.
Still, she wonders to
herself: What do people in the outside world experience when they see
the various colors? What is it like for them to see red or green? One
day her captors release her. She is free at last to see things with their real
colors (and free too to scrub off the awful black and white paint that covers
her body). She steps outside her room into a garden full of flowers. "So,
that is what it is like to experience red," she exclaims, as she sees a
red rose. "And that," she adds, looking down at the grass, "is
what it is like to experience green."
Mary here seems to make
some important discoveries. She seems to find out things she did not know
before. How can that be, if, as seems possible, at least in principle, she has
all the physical information there is to have about color and color vision --
if she knows all the pertinent physical facts?
One popular explanation
among philosophers (so-called ‘qualia freaks’) is that that there is a realm of
subjective, phenomenal qualities associated with color, qualities the intrinsic
nature of which Mary comes to discover upon her release, as she herself
undergoes the various new color experiences. Before she left her room, she only
knew the objective, physical basis of those subjective qualities, their causes
and effects, and various relations of similarity and difference. She had no
knowledge of the subjective qualities in themselves.
This explanation is not
available to the physicalist. If what it is like for someone to experience red
is one and the same as some physical quality, then Mary already knows that
while in her room. Likewise, for experiences of the other colors. For Mary
knows all the pertinent physical facts. What, then, can the physicalist say?
Some physicalists respond
that knowing what it is like is know-how and nothing more. Mary acquires
certain abilities, specifically in the case of red, the ability to recognize
red things by sight alone, the ability to imagine a red expanse, the ability to
remember the experience of red. She does not come to know any new
information, any new facts about color, any new qualities. This is the view of
David Lewis (1990) and Lawrence Nemirow (1990).
The Ability Hypothesis, as
it is often called, is more resilient than many philosophers suppose (see Tye
forthcoming (a)). But it has difficulty in properly accounting for our
knowledge of what it is like to undergo experiences of determinate hues while
we are undergoing them. For example, I can know what it is like to experience
red-17, as I stare at a rose of that color. Of course, I don't know the hue as
red-17. My conception of it is likely just that shade of red. But I
certainly know what it is like to experience the hue while it is present. Unfortunately,
I lack the abilities Lewis cites and so does Mary even after she leaves her
cell. She is not able to recognize things that are red-17 as red-17 by sight. Given
the way human memory works and the limitations on it, she lacks the concept
red-17. She has no mental template that is sufficiently fine-grained to permit
her to identify the experience of red-17 when it comes again. Presented with
two items, one red-17 and the other red-18, in a series of tests, she cannot
say with any accuracy which experience her earlier experience of the rose
matches. Sometimes she picks one; at other times she picks the other. Nor is
she able afterwards to imagine things as having hue, red-17, or as having that
very shade of red the rose had; and for precisely the same reason.
The Ability Hypothesis
appears to be in trouble. An alternative physicalist proposal is that Mary in
her room lacks certain phenomenal concepts, certain ways of thinking
about or mentally representing color experiences and colors. Once she leaves
the room, she acquires these new modes of thought as she experiences the
various colors. Even so, the qualities the new concepts pick out are ones she
knew in a different way in her room, for they are physical or functional
qualities like all others.
One problem this approach
faces is that it seems to imply that Mary does not really make a new discovery
when she says, "So, that is what it is like to experience red." Upon
reflection, however, it is far from obvious that this is really a consequence. For
it is widely accepted that concepts or modes of presentation are involved in
the individuation of thought-contents, given one sense of the term ‘content’ --
the sense in which thought-content is whatever information that-clauses provide
that suffices for the purposes of even the most demanding rationalizing
explanation. In this sense, what I think, when I think that Cicero was an
orator, is not what I think when I think that Tully was an orator. This is
precisely why it is possible to discover that Cicero is Tully. The thought that
Cicero was an orator differs from the thought that Tully was an orator not at
the level of truth-conditions -- the same singular proposition is partly
constitutive of the content of both -- but at the level of concepts or mode of
presentation. The one thought exercises the concept Cicero; the other
the concept Tully. The concepts have the same reference, but they
present the referent in different ways and thus the two thoughts can play
different roles in rationalizing explanation.
So, there is no real
difficulty in holding both that Mary comes to know some new things upon her
release, while already knowing all the pertinent real-world physical facts,
even though the new experiences she undergoes and their introspectible
qualities are wholly physical. In an ordinary, everyday sense, Mary's knowledge
increases. And that is all the physicalist needs to answer the Knowledge
Argument. (The term ‘fact’, I should add, is itself ambiguous. Sometimes it is
used to pick out real-world states of affairs alone; sometimes it is used for
such states of affairs under certain conceptualizations. When I speak of the
physical facts above, I should be taken to refer either to physical states of
affairs alone or to those states of affairs under purely physical conceptualizations.
For more on ‘fact’, see Tye 1995.)
Some philosophers insist
that the difference between the old and the new concepts in this case is such
that there must be a difference in the world between the properties these
concepts stand for or denote (Jackson 1993, Chalmers 1996). Some of these
properties Mary knew in her cell; others she becomes cognizant of only upon her
release. The physicalist is committed to denying this claim.
The issues here are
complex. If a necessary a posteriori identity claim about properties requires
for its truth that one or the other of the rigid terms flanking the identity
sign be a priori connected to a different property from the one it denotes (so
that the mode of presentation is wholly distinct from the referent) then it may
seem that physicalism about qualia is in trouble. For phenomenal terms are
often viewed as picking out phenomenal qualities via those very qualities. (This
point, or one very like it, is sometimes put within the framework of
two-dimensional modal semantics by saying that phenomenal terms have the same
primary and secondary intensions). But even granting this claim, the above view
of necessary a posteriori identities entails that physicalism about qualia is
false only if it is true that the physical term on the right hand side of the
identity sign itself refers via a mode of presentation that is the same as the
referent (so that its primary intension is the same as its secondary one). And,
in general, that cannot be correct. To see this, consider a purely theoretical
identity, that between H2O and a certain quantum-mechanical system. The
identity claim here is necessary a posteriori, assuming that ‘H2O’
and the appropriate quantum-mechanical designator are both rigid. So, if a
condition of a property identity being necessary a posteriori is that one or
other of the designators express a concept whose mode of presentation is
different from its referent, then we have, with this example, a case where the
mode of presentation and the referent come apart for at least one of the
theoretical terms (and arguably for both). Why not, then, for the rigid
physical designator in the case of a phenomenal-physical identity?
Another famous
anti-reductionist thought-experiment concerning qualia appeals to the possibility
of zombies. A philosophical zombie is a molecule by molecule duplicate of a
sentient creature, a normal human-being, for example, but who differs from that
creature in lacking any phenomenal consciousness. For me, as I lie on
the beach, happily drinking some wine and watching the waves, I undergo a
variety of visual, olfactory, and gustatory experiences. But my zombie twin
experiences nothing at all. He has no phenomenal consciousness. Since my twin
is an exact physical duplicate of me, his inner psychological states will be functionally
isomorphic with my own (assuming he is located in an identical environment). Whatever
physical stimulus is applied, he will process the stimulus in the same way as I
do, and produce exactly the same behavioral responses. Indeed, on the
assumption that non-phenomenal psychological states are functional states (that
is, states definable in terms of their role or function in mediating between
stimuli and behavior), my zombie twin has just the same beliefs, thoughts, and
desires as I do. He differs from me only with respect to experience. For him,
there is nothing it is like to stare at the waves or to sip wine.
The hypothesis that there
can be philosophical zombies is not normally the hypothesis that such zombies
are nomically possible, that their existence is consistent with the
actual laws of nature. Rather the suggestion is that zombie replicas of this
sort are at least imaginable and hence metaphysically possible.
Philosophical zombies pose
a serious threat to any sort of physicalist view of qualia. To begin with, if
zombie replicas are metaphysically possible, then there is a simple argument
that seems to show that phenomenal states are not identical with internal,
objective, physical states. Suppose objective, physical state P can
occur without phenomenal state S in some appropriate zombie replica (in
the metaphysical sense of ‘can’ noted above). Intuitively S cannot occur
without S. Pain, for example, cannot be felt without pain. So, P
has a modal property S lacks, namely the property of possibly
occurring without S. So, by Leibniz' Law (the law that for anything x
and for anything y, if x is identical with y then x
and y share all the same properties), S is not identical
with P.
Secondly, if a person
microphysically identical with me, located in an identical environment (both
present and past), can lack any phenomenal experiences, then facts
pertaining to experience and feeling, facts about qualia, are not necessarily
fixed or determined by the objective microphysical facts. And this the
physicalist cannot allow, even if she concedes that phenomenally conscious
states are not strictly identical with internal, objective, physical states. For
the physicalist, whatever her stripe, must at least believe that the microphysical
facts determine all the facts, that any world that was exactly like ours in all
microphysical respects (down to the smallest detail, to the position of every
single boson, for example) would have to be like our world in all respects
(having identical mountains, lakes, glaciers, trees, rocks, sentient creatures,
cities, and so on).
One well-known physicalist
reply to the case of zombies (Loar 1990) is to grant that they are conceptually
possible, or at least that there is no obvious contradiction in the idea
of a zombie, while denying that zombies are metaphysically possible. Since the
anti-physicalist argument requires metaphysical possibility -- mere conceptual
possibility will not suffice -- it now collapses. That conceptual possibility
is too weak for the anti-physicalist's purposes (at least without further
qualification and argument) is shown by the fact that it is conceptually
possible that I am not Michael Tye (that I am an impostor or someone
misinformed about his past) even though, given the actual facts, it is
metaphysically impossible.
Functionalism
is the view that individual qualia have functional natures, that the phenomenal
character of, e.g., pain is one and the same as the property of playing
such-and-such a causal or teleofunctional role in mediating between physical
inputs (e.g., body damage) and physical outputs (e.g., withdrawal behavior). On
this view (Lycan 1987), qualia are multiply physically realizable. Inner states
that are physically very different may nonetheless feel the same. What is
crucial to what it is like is functional role, not underlying hardware.
There are two famous
objections to functionalist theories of qualia: the Inverted Spectrum and the
Absent Qualia Hypothesis. The first move in the former objection consists in
claiming that you might see red when I see green and vice-versa; likewise for
the other colors so that our color experiences are phenomenally inverted. This
does not suffice to create trouble for the functionalist yet. For you and I are
surely representationally different here: for example, you have a visual
experience that represents red when I have one that represents green. And that
representational difference brings with it a difference in our patterns of
causal interactions with external things (and thereby a functional difference).
This reply can be handled
by the advocate of inverted qualia by switching to a case in which we both have
visual experiences with the same representational contents on the same
occasions while still differing phenomenally. Whether such cases are really
metaphysically possible is open to dispute, however. Certainly, those
philosophers who are representationalists about qualia (see Section VII) would
deny their possibility. Indeed, it is not even clear that such cases are
conceptually possible (Harrison 1973, Hardin 1993, Tye 1995). But leaving this
to one side, it is far from obvious that there would not have to be some
salient fine-grained functional differences between us, notwithstanding our
gross functional identity.
Consider a computational
example. For any two numerical inputs, M and N, a given computer
always produces as outputs the product of M and N. There is a
second computer that does exactly the same thing. In this way, they are functionally
identical. Does it follow that they are running exactly the same program? Of
course, not! There are all sorts of programs that will multiply together two
numbers. These programs can differ dramatically. At one gross level the
machines are functionally identical, but at lower levels the machines can be
functionally different.
In the case of you and me,
then, the opponent of inverted qualia can claim that, even if we are
functionally identical at a coarse level - we both call red things ‘red’, we
both believe that those things are red on the basis of our experiences, we both
are caused to undergo such experiences by viewing red things, etc. - there are
necessarily fine-grained differences in our internal functional organization. And
that is why our experiences are phenomenally different.
Some philosophers will no
doubt respond that it is still imaginable that you and I are functionally
identical in all relevant respects yet phenomenally different. But this
claim presents a problem at least for those philosophers who oppose
functionalism but who accept physicalism. For it is just as easy to imagine
that there are inverted qualia in molecule-by-molecule duplicates (in the same
external, physical settings) as it is to imagine inverted qualia in functional
duplicates. If the former duplicates are really metaphysically impossible, as
the physicalist is committed to claiming, why not the latter? Some further
convincing argument needs to be given that the two cases are disanalogous. As
yet, to my mind, no such argument has been presented. (Of course, this response
does not apply to those philosophers who take the view that qualia are
irreducible, non-physical entities. However, these philosophers have other
severe problems of their own. In particular, they face the problem of
phenomenal causation. Given the causal closure of the physical, how can qualia
make any difference? For more here, see Tye 1995, Chalmers 1996).
The absent qualia
hypothesis is the hypothesis that functional duplicates of sentient creatures
are possible, duplicates that entirely lack qualia. For example, one writer
(Block (1980)) asks us to suppose that a billion Chinese people are each given
a two-way radio with which to communicate with one another and with an
artificial (brainless) body. The movements of the body are controlled by the
radio signals, and the signals themselves are made in accordance with
instructions the Chinese people receive from a vast display in the sky which is
visible to all of them. The instructions are such that the participating
Chinese people function like individual neurons, and the radio links like
synapses, so that together the Chinese people duplicate the causal organization
of a human brain. Whether or not this system, if it were ever actualized, would
actually undergo any feelings and experiences, it seems coherent to
suppose that it might not. But if this is a real metaphysical possibility, then
qualia do not have functional essences.
One standard functionalist
reply to cases like the China-body system is to bite the bullet and to argue
that however strange it seems, the China-body system could not fail to undergo
qualia. The oddness of this view derives, according to some functionalists
(Lycan 1987), from our relative size. We are each so much smaller than the
China-body system that we fail to see the forest for the trees. Just as a
creature the size of a neuron trapped inside a human head might well be wrongly
convinced that there could not be consciousness there, so we too draw the wrong
conclusion as we contemplate the China-body system. It has also been argued
(e.g., by Shoemaker 1975) that any system that was a full functional duplicate
of one of us would have to be subject to all the same beliefs, including
beliefs about its own internal states. Thus the China-Body system would have to
believe that it experiences pain; and if it had beliefs of this sort, then it
could not fail to be the subject of some experiences (and hence some states
with phenomenal character). If this reply is successful, what it shows is that
the property of having some phenomenal character or other has a functional
essence. But it does not show that individual qualia are functional in nature. Thus
one could accept that absent qualia are impossible while also holding that
inverted spectra are possible (see, e.g., Shoemaker 1975).
Our grasp
of what it is like to undergo phenomenal states is supplied to us by
introspection. We also have an admittedly incomplete grasp of what goes on objectively
in the brain and the body. But there is, it seems, a vast chasm between the
two. It is very hard to see how this chasm in our understanding could ever be
bridged. For no matter how deeply we probe into the physical structure of
neurons and the chemical transactions which occur when they fire, no matter how
much objective information we come to acquire, we still seem to be left with
something that we cannot explain, namely, why and how such-and-such objective,
physical changes, whatever they might be, generate so-and-so subjective
feeling, or any subjective feeling at all.
This is the famous
"explanatory gap" for qualia (Levine 1983). Some say that the
explanatory gap is unbridgeable and that the proper conclusion to draw from it
is that there is a corresponding gap in the world. Experiences and feelings
have irreducibly subjective, non-physical qualities (Jackson 1993, Chalmers
1996). Others take essentially the same position on the gap while insisting
that this does not detract from a purely physicalist view of experiences and
feelings. What it shows rather is that some physical qualities or states are
irreducibly subjective entities (Searle 1992). Others hold that the explanatory
gap may one day be bridged but we currently lack the concepts to bring the
subjective and objective perspectives together. On this view, it may turn out
that qualia are physical, but we currently have no clear conception as to how
they could be (Nagel 1974). Still others adamantly insist that the explanatory
gap is, in principle, bridgeable but not by us or by any creatures like us. Experiences
and feelings are as much a part of the physical, natural world as life,
digestion, DNA, or lightning. It is just that with the concepts we have and the
concepts we are capable of forming, we are cognitively closed to a full,
bridging explanation by the very structure of our minds (McGinn 1991).
Another view that has been
gaining adherents of late is that there is a real, unbridgeable gap, but it has
no consequences for the nature of consciousness and physicalist or
functionalist theories thereof. On this view, there is nothing in the gap that
should lead us to any bifurcation in the world between experiences and
feelings on the one hand and physical or functional phenomena on the other. There
aren't two sorts of natural phenomena: the irreducibly subjective and the
objective. The explanatory gap derives from the special character of phenomenal
concepts. These concepts mislead us into thinking that the gap is deeper
and more troublesome than it really is.
On one version of this
view, phenomenal concepts are just indexical concepts applied to phenomenal
states via introspection (see Lycan 1996). On an alternative version of the
view, phenomenal concepts are very special, first-person concepts different in
kind from all others (see Tye forthcoming (b)). This response to the
explanatory gap obviously bears affinities to the second physicalist response I
sketched in Section III to the Knowledge Argument.
There is no general
agreement on how the gap is generated and what it shows.
In the
past, philosophers have often appealed directly to introspection on behalf of
the view that qualia are intrinsic, non-intentional features of experiences. Recently,
a number of philosophers have claimed that introspection reveals no such
qualities (Harman 1990, Dretske 1995, Tye 1995). Suppose you are facing a white
wall, on which you see a bright red, round patch of paint. Suppose you are
attending closely to the color and shape of the patch as well as the
background. Now turn your attention from what you see out there in the world
before you to your visual experience. Focus upon your awareness of the
patch as opposed to the patch of which you are aware. Do you find
yourself suddenly acquainted with new qualities, qualities that are intrinsic
to your visual experience in the way that redness and roundness are qualities
intrinsic to the patch of paint? According to some philosophers, the answer to
this question is a resounding ‘No’. As you look at the patch, you are aware of
certain features out there in the world. When you turn your attention inwards
to your experience of those features, you are aware of the very same
features together with the fact that your mental state is representing them; no
new features of your experience over and above its representing red, round,
etc. are revealed. In this way, your visual experience is transparent or
diaphanous. When you try to examine it, you see right though it, as it were, to
the qualities you were experiencing all along in being a subject of the
experience, qualities your experience is of.
This point holds good even
if you are hallucinating and there is no real patch of paint on the wall before
you. Still you have an experience of there being a patch of paint out
there with a certain color and shape. It's just that this time your experience
is a misrepresentation. And if you turn your attention inwards to your
experience, you will ‘see’ right through it again to those very same qualities.
These observations suggest
that qualia, the immediately ‘felt’ qualities of experiences of which we are
cognizant when we attend to them introspectively, are representational
qualities -- qualities like representing red, representing round, representing
a red, round shape, and so on. Not everyone agrees that this is what
introspection shows (see Block 1991). Perhaps qualia are not presented to us in
introspection as intrinsic, non-intentional features of our experiences.
Still it does not follow from this that we are not introspectively acquainted
with intrinsic qualia at all. For we do know on the basis of introspection what
it is like to undergo a visual experience of blue, say. So, if what a state is
like is a matter of which intrinsic, non-intentional features it tokens, then
obviously we are introspectively aware of such features (in the de re sense of
‘of’). On this view, whether qualia are intrinsic, non-intentional features of
experiences is a theoretical matter. Introspection does not settle the matter
one way or the other.
Talk of the
ways things look and feel is intensional. If I have a red after-image as a
result of a flashbulb going off, the spot I ‘see’ in front of the
photographer's face looks red, even though there is no such spot. If I live in
a world in which all and only things that are purple are poisonous, it is still
the case that an object that looks purple to me does not thereby look poisonous
(in the phenomenal sense of ‘looks’). If I feel a pain in a leg, I need not
even have a leg. My pain might be a pain in a phantom limb. Facts such as these
have been taken to provide further support for the contention that qualia are
representational qualities.
If qualia are indeed
representational, an important question arises: which aspects of the
representational content of an experience are relevant to its phenomenal
character, to what it is like to have the experience? Obviously not all aspects
of content are phenomenally relevant. If you and I see a telescope from the
same viewing angle, for example, then even if I do not recognize it as a
telescope and you do (so that our experiences differ representationally at this
level), the way the telescope looks to both of us is likely pretty much
the same (in the phenomenal sense of ‘looks’). Likewise, if a child is viewing
the same item from the same vantage point, her experience will likely be pretty
similar to yours and mine too. Phenomenally, our experiences are all very much
alike, notwithstanding certain higher-level representational differences. This,
according to some representationalists, is because we all have experiences that
represent to us the same 3-D surfaces, edges, colors, and surface-shapes plus a
myriad of other surface details.
The representation we share
here has a content much like that of the 2 1/2-D sketch posited by David Marr
in his famous theory of vision (1982) to which further shape and color
information has been appended (for details, see Tye 1995). This content is
plausibly viewed as nonconceptual. It forms the output of the early, largely
modular sensory processing and the input to one or another system of
higher-level cognitive processing. Representationalists sometimes claim that it
is here at this level of content that qualia are to be found (see Dretske 1995,
Tye 1995; for an opposing representational view, see McDowell 1994).
Representationalists about
qualia are typically also externalists about representational content. On this
view, what a given experience represents is metaphysically determined at least,
in part, by factors in the external environment. Thus, it is usually held,
microphysical twins can differ with respect to the representational contents of
their experiences. If these differences in content are of the right sort then,
according to the wide representationalist, microphysical twins cannot fail
to differ with respect to the phenomenal character of their experiences. What
makes for a difference in representational content in microphysical duplicates
is some external difference, some connection between the subjects and items in
their respective environments. The generic connection is sometimes called
‘tracking’, though there is no general agreement as to in what exactly tracking
consists.
On wide representationalism,
qualia (like meanings) ain't in the head. The classic, Cartesian-based picture
of experience and its relation to the world is thus turned upside down. Qualia
are not intrinsic qualities of inner ideas of which their subjects are directly
aware, qualities that are necessarily shared by internal duplicates however
different their environments may be. Rather, they are extrinsic qualities fixed
by certain external relations between individuals and their environments.
Representationalism, as I
have presented it so far, is an identity thesis with respect to qualia: qualia
are supposedly one and the same as certain representational qualities. Sometimes
a weaker supervenience thesis is adopted, according to which it is
metaphysically necessary that experiences alike with respect to their
representational contents are alike with respect to their qualia. Obviously,
the supervenience thesis leaves open the further question as to the essential
nature of qualia.
Objections to
representationalism often take the form of putative counter-examples. One class
of these consists of cases in which, it is claimed, experiences have the same
representational content but different phenomenal character. Christopher
Peacocke adduces examples of this sort in his 1983. According to some (e.g.,
Block 1990, Shoemaker forthcoming), the Inverted Spectrum also supplies an
example that falls into this category. Another class is made up of problem
cases in which allegedly experiences have different representational contents
(of the relevant sort) but the same phenomenal character. Ned Block's Inverted
Earth example (1990) is of this type. The latter cases only threaten strong
representationalism, the former are intended to refute representationalism in
both its strong and weaker forms. Counter-examples are also sometimes given in
which supposedly experience of one sort or another is present but in which
there is no state with representational content. Swampman (Davidson 1986) --
the molecule by molecule replica of one of us , formed accidentally by the
chemical reaction that occurs in a swamp when a partially submerged log is hit
by lightning -- is one such counter-example, according to some philosophers. But
there are more mundane cases. Consider the exogenous feeling of depression. That,
it may seem, has no representational content. Cases of the third sort,
depending upon how they are elucidated further, can pose a challenge to either
strong or weaker versions of representationalism.
I lack the space to go
through all these objections. I shall discuss briefly just one: Inverted Earth.
Inverted Earth is an imaginary planet, on which things have complementary
colors to the colors of their counterparts on Earth. The sky is yellow, grass
is red, ripe tomatoes are green, and so on. The inhabitants of Inverted Earth
undergo psychological attitudes and experiences with inverted intentional
contents relative to those of people on Earth. They think that the sky is
yellow, see that grass is red, etc. However, they call the sky ‘blue’, grass
‘green’, ripe tomatoes ‘red’, etc. just as we do. Indeed, in all respects
consistent with the alterations just described, Inverted Earth is as much like
Earth as possible.
In Block's original version
of the tale, mad scientists insert color-inverting lenses in your eyes and take
you to Inverted Earth, where you are substituted for your Inverted Earth twin
or doppelganger. Upon awakening, you are aware of no difference, since the
inverting lenses neutralize the inverted colors. You think that you are still
where you were before. What it is like for you when you see the sky or anything
else is just what it was like on earth. But after enough time has passed, after
you have become sufficiently embedded in the language and physical environment
of Inverted Earth, your intentional contents will come to match those of the
other inhabitants. You will come to believe that the sky is yellow, for
example, just as they do. Similarly, you will come to have a visual experience
that represents the sky as yellow. For the experiential state you now undergo,
as you view the sky, is the one that, in you, now normally tracks yellow
things. So, the later you will come to be subject to inner states that are
intentionally inverted relative to the inner states of the earlier you, while the
phenomenal aspects of your experiences will remain unchanged. It follows that
strong representationalism of the externalist sort is false.
Perhaps the simplest reply
that the strong representationalist can make with respect to this objection is
to deny that there really is any change in normal tracking with respect to
color, at least as far as your experiences go. "Normal", after all,
has both teleological and nonteleological senses. If what an experience
normally tracks is what nature designed it to track, what it has as its
biological purpose to track, then shifting environments from Earth to Inverted
Earth will make no difference to normal tracking and hence no difference to the
representational contents of your experiences. The sensory state that nature
designed in your species to track blue in the setting in which your species
evolved will continue to do just that even if through time, on Inverted Earth,
in that alien environment, it is usually caused in you by looking at yellow
things.
The suggestion that
tracking is teleological in character, at least for the case of basic
experiences, goes naturally with the plausible view that states like feeling
pain or having a visual sensation of red are phylogenetically fixed (Dretske
1995). However, it encounters serious difficulties with respect to the Swampman
case mentioned above. On a cladistic conception of species, Swampman is not
human. Indeed, lacking any evolutionary history, he belongs to no species at
all. His inner states play no teleological role. Nature did not design any of
them to do anything. So, if phenomenal character is a certain sort of
teleo-representational content, then Swampman has no experiences and no qualia.
There are alternative
replies available to the strong representationalist (see Lycan 1996, Tye 1998)
in connection with the Inverted Earth problem. These involve either denying
that qualia do remain constant with the switch to Inverted Earth or arguing
that a non-teleological (but still wide) account of sensory content may be elaborated,
under which qualia stay the same.
Do frogs
have qualia? Or fish? What about honey bees? Somewhere down the phylogenetic
scale phenomenal consciousness ceases. But where? It is sometimes supposed that
once we begin to reflect upon much simpler beings than ourselves -- snails, for
example -- we are left with nothing physical or structural that we could
plausibly take to help us determine whether they are phenomenally conscious
(Papineau 1994). There is really no way of our knowing if spiders are
subject to states with qualia, as they spin their webs, or if fish undergo any
phenomenal experiences, as they swim about in the sea.
Representationalism has the
beginnings of an answer to the above questions. If qualia are, by their very
nature, qualities of states that carry information about certain features,
internal or external, states that form the outputs of sensory modules and stand
ready and available to make a direct difference to beliefs and desires, then
creatures that are incapable of reasoning, of changing their behavior in light
of assessments they make, based upon information provided to them by sensory
stimulation of one sort or another, are not phenomenally conscious. Tropistic
organisms, on this view, feel and experience nothing. They have no qualia. They
are full-fledged unconscious automata or zombies, rather as blindsight subjects
are restricted unconscious automata or partial zombies with respect to a range
of visual stimuli.
Consider, for example, the
case of plants. There are many different sorts of plant behavior. Some plants
climb, others eat flies, still others catapult out seeds. Many plants close
their leaves at night. The immediate cause of these activities is something
internal to the plants. Seeds are ejected because of the hydration or
dehydration of the cell walls in seed pods. Leaves are closed because of water
movement in the stems and petioles of the leaves, itself induced by changes in
the temperature and light. These inner events or states are surely not
phenomenal. There is nothing it is like to be a Venus Fly Trap or a
Morning-Glory.
The behavior of plants is
inflexible. It is genetically determined and, therefore, not modifiable by
learning. Natural selection has favored the behavior, since historically it has
been beneficial to the plant species. But it need not be now. If, for example,
flies start to carry on their wings some substance that sickens Venus Fly Traps
for several days afterwards, this will not have any effect on the plant
behavior with respect to flies. Each Venus Fly trap will continue to snap at
flies as long as it has the strength to do so.
Plants do not learn from
experience. They do not acquire beliefs and change them in light of things that
happen to them. Nor do they have any desires. To be sure, we sometimes speak as
if they do. We say that the wilting daffodils are just begging to be watered. But
we recognize full well that this is a harmless facon de parler. What we mean is
that the daffodils need water. There is here no goal-directed behavior,
no purpose, nothing that is the result of any learning, no desire for
water.
Plants, on the
representational view, are not subject to any qualia. Nothing that goes on
inside them is poised to make a direct difference to what they believe or
desire, since they have no beliefs or desires.
Reasoning of the above sort
can be used to make a case that even though qualia do not extend to plants and
paramecia, qualia are very widely distributed in nature (see Tye 1997). Of
course, such a case requires decisions to be made about the attribution of
beliefs and desires to much simpler creatures. And such decisions are likely to
be controversial in some cases. Moreover, representationalism itself is a very
controversial position. The general topic of the origins of qualia is not one
on which philosophers have said a great deal.
Copyright © 1997 by
Michael Tye
tye@vm.temple.edu
First published: August
20, 1997
Content last modified: November 1, 1997