David Papineau
Phenomenal and
Perceptual Concepts
___________________________________________________________________________________
Contents
1 Introduction
2 Perceptual
Concepts
2.1 Perceptual Concepts are not Demonstrative
2.2 Perceptual Concepts as Stored Templates
2.3 Perceptual Semantics
2.4 Perceptually Derived Concepts
3 Phenomenal
Concepts
3.1 The Quotational-Indexical
Model
3.2 Phenomenal Concepts as
Perceptual Concepts
3.3 Phenomenal Use and Mention
3.4 A Surprising Implication
4 Phenomenal
Concepts and Anti-Materialist Arguments
4.1
The Knowledge Argument
4.2 I am not now having or imagining THAT experience
4.3 Semantic Stability and A
Posteriori Necessity
4.4 Kripke’s Original Argument
4.5 The
Intuition of Distinctness
5 Chalmers on
Type-B Physicalism
5.1 Chalmers’ Dilemma
5.2 The Dilemma Embraced
5.3 The First Horn
5.4 TheSecondHorn
________________________________________________________________
1 Introduction
Phenomenal
concepts are common coin among nearly all contemporary philosophers working on
consciousness. They are recognized both
by ontological dualists, who take them to refer to distinctive non-material (phenomenal)
properties, and by the majority of contemporary materialists, who respond that
phenomenal concepts are distinctive only at a conceptual level, and
refer to nothing except material properties that can also be referred to using
non-phenomenal material concepts.
In speaking of the
majority of contemporary materialists, I have in mind the school of thought
that David Chalmers (2003a) has dubbed ‘type-B physicalism’. In effect, type-B physicalism is a concession
to the classic anti-materialist arguments of Frank Jackson (1986) and Saul
Kripke (1980). Older (type-A) physicalists
took all concepts of conscious states to be functional concepts—that is,
concepts that referred by association with causal roles. Because of this, they denied the initial
premises of Jackson’s and Kripke’s arguments.
In response to Jackson’s ‘Mary’ argument, they argued that any
functional concepts of conscious states would have been be available to Mary
before she left her room, and so that there was no sense in which she acquired
any new knowledge of ‘what it is like’ to see something as red. Relatedly, in response to Kripke’s argument,
they argued that it was inconceivable, and so obviously impossible, that a
being could be fully physically identical to us yet lack consciousness. However, these responses to Jackson and
Kripke are now widely agreed to be unsatisfactory. It seems clear that the pre-emergence Mary
does lack some concepts of colour experiences, and moreover that zombies are at
least conceivable. By recognizing phenomenal
concepts, type-B physicalists aim to concede this much to Jackson and
Kripke. At the same time, they argue
that, once we do recognize phenomenal concepts, then we can see that the
subsequent stages of Jackson’s and Kripke’s arguments do not provide a valid
route to ontologically dualist conclusions.
(Cf. Loar 1990, Papineau 2002 chs 2 and 3.)
What is the nature
of phenomenal concepts? Here there is
far less consensus. Among those who
trade in phenomenal concepts, some take them to be sui generis (Tye, 2003, Chalmers, 2003b), while
others have variously likened them to recognitional concepts (Loar, 1990), to
demonstratives (Horgan 1984, Papineau 1993a, Perry 2001), or to quotational
terms (Papineau 2002, Balog forthcoming).
In my Thinking
about Consciousness (2002), I developed a ‘quotational-indexical’ of
phenomenal concepts account on roughly the following lines. To have a phenomenal concept of some
experience, you must be able introspectively to focus on it when you have it,
and to recreate it imaginatively at other times; given these abilities, you can then form
terms with the structure the experience:
—-, where the gap is filled either by a current experience, or by an
imaginative recreation of an experience;
these terms then comprise a distinctive way of referring to the
experience at issue.
In the book I
argued that this account of phenomenal concepts not only allows a satisfactory
materialist response to Jackson’s and Kripke’s arguments, but also explains why
dualism seems so compelling even to those unfamiliar with those arguments. According to my analysis, we all experience a
basic ‘intuition of mind-brain distinctness’, which is prior to any
philosophical investigation (and indeed which lends a spurious plausibility to
the standard anti-materialist arguments, by independently adding credibility to
their conclusions). However, once we
understand the structure of phenomenal concepts, I argued, we can see how this
intuition arises, and why it provides no real reason to doubt materialism.
In this paper, I
want to return to the topic of phenomenal concepts. It now seems to me that the treatment in Thinking
about Consciousness was inadequate in various respects. Here I want to try to improve on that
account. In particular, I shall develop
an extended comparison of phenomenal concepts with what I shall call
‘perceptual concepts’, hoping thereby to throw the nature of phenomenal
concepts into clearer focus.
While the position
I shall develop in this paper will involve some significant revisions of the
claims made in my book, I think that the main arguments in the book are robust
with respect to these revisions. In
particular, the responses to Jackson and Kripke will stand pretty much as
before, and an explanation of the persistent ‘intuition of distinctness’ will
continue to be available.
The revised
account will also enable me to deal with a common worry about phenomenal
concepts[1]. Suppose Mary has come out of her room, seen a
red rose, and as a result acquired a phenomenal concept of the experience of
seeing something red (though she mightn’t yet know that this experience is conventionally
so-called). On most account of
phenomenal concepts, including the one developed in my book, any exercise of
this phenomenal concept will demand the presence of the experience itself or an
imaginatively recreated exemplar thereof.
The trouble, however, is that it seems quite possible for Mary to think
truly, using her new phenomenal concept, I
am not now having that experience (nor recreating it in my imagination)—but
this would be ruled out if any exercise of her phenomenal concept did indeed depend
on the presence of the experience or its imaginative recreation. The revised account of phenomenal concepts to
be developed here will not require this, and so will be able to explain Mary’s
problematic thought.
The rest of this
article contains four sections. The next
two analyse perceptual and phenomenal concepts respectively. The penultimate section checks that my
revised account of phenomenal concepts will still serve to block the standard
arguments for dualism. The final section
defends my position against a recent argument by David Chalmers against the
whole Type-B strategy of defending physicalism by appeal to phenomenal
concepts.
2 Perceptual
Concepts
2.1 Perceptual Concepts are not Demonstrative
Let me turn away
from phenomenal concepts for a while, and instead consider perceptual concepts. Getting clear about perceptual concepts will
stand us in good stead when we turn to the closely related category of
phenomenal concepts.
We can start with
this kind of case. You see a bird at the
bottom of your garden. You look at it
closely, and at the same time think I
haven’t seen THAT in here before.
Later on you can recall the bird in visual imagination, perhaps thinking
I wonder if THAT was a migrant. In addition, on further perceptual encounters
with birds, you sometimes take some bird to be the same bird again, and can
again form further thoughts about it, such as THAT bird has a pleasant song.
(Let me leave it open for the moment whether you are thinking of a
particular bird or a type of bird; I
shall return to this shortly.)
In examples like
this, I shall say that subjects are exercising perceptual concepts. Perceptual concepts allow subjects to think
about perceptible entities. Such
concepts are formed when subjects initially perceive the relevant entities, and
are re-activated by latter perceptual encounters. Subjects can also use these concepts to think
imaginatively about those entities even when they are not present.
Now, it is tempting
to view concepts of this kind as ‘demonstrative’. For one thing, it is natural
to express these concepts using demonstrative words, as the above examples show
(‘. . . THAT . . .’). Moreover, uses of perceptual concepts involve
a kind of perceptual attention or imaginative focus, and this can seem
analogous to the overt pointing or other indicative acts that accompany the use
of verbal demonstratives.
However, I think
it is quite wrong to classify perceptual concepts as demonstratives. If anything is definitive of demonstrative
terms, it is surely that they display some species of characterlikeness. By this I mean that the referential value of
the term is context-dependent—the selfsame term will refer to different items
in different contexts. However, there
seems nothing characterlike about the kind of perceptual concept illustrated in
the above examples. Whenever it is
exercised, your perceptual concept refers to the same bird. When you use the concept in question, you
don’t refer to one bird on the first encounter, yet some possibly different
bird when later encountering or visually imagining it. Your concept picks out the same bird whenever
it is exercised.
It is possible to
be distracted from this basic point by failing to distinguish clearly between
perceptual concepts and their linguistic expression. If I want to express some perceptual thought in
language, then there may be no alternative to the use of demonstrative words. In order to convey my thought to you, I may
well say ‘That bird has a present song’, while indicating some nearby
bird. And I agree that the words here
used—‘that bird’—are demonstrative, in that they will refer to different birds
in different contexts of use. But this
does not mean that my concept itself is demonstrative. As I have just urged, my concept itself will
refer to the same bird whenever it is exercised.
The reason we
often resort to demonstrative words to convey thoughts involving
non-demonstrative perceptual concepts is simply that there is often no publicly
established linguistic term to express our concept. In such cases, we can nevertheless often get our
ideas across by demonstratively indicating some instance of what we are
thinking about. Of course, this
possibility assumes that some such instance is available to be demonstrated—if
there isn’t, then we may simply find ourselves unable to express what we are
thinking to an audience.
By insisting that
perceptual concepts are not demonstrative, even if the words used to express
them are, I do not necessarily want to exclude characterlikeness from every
aspect of the mental realm. Millikan (1990)
has argued that mental indexicality plays no ineliminable role in the explanation
of action, against Perry (1979) and much current orthodoxy, and I find her case
on this particular point persuasive. Even so, I am open to the possibility that primitive
mental demonstratives may play some role in pre-conceptual attention (what
was THAT?) and also to the possibility that there may be characterlike
mental terms constructed with the help of predicates (I’m frightened of THAT
DOG-ie the dog in the corner of the room).[2] In both these kinds of case I allow that the
capitalised expressions may express genuinely characterlike mental terms—that
is, repeatable mental terms that have different referents on different
occasions of use. My claim in this
section has only been that perceptual concepts in particular are
not characterlike in this sense, but carry the same referent with them from one
occasion of use to another.
2.2 Perceptual
Concepts as Stored Templates
I take perceptual
concepts to involve a phylogenetically old mode of thought that is common to
both humans and animals. We can
helpfully think of perceptual concepts as involving stored sensory templates. These templates will be set up on initial encounters
with the relevant referents. They will
then be reactivated on later perceptual encounters, via matches between
incoming stimuli and stored template—perhaps the incoming stimuli can be
thought of as ‘resonating’ with the stored pattern and thereby being
amplified. Such stored templates can
also be activated autonomously even in the absence of any such incoming
stimuli—these will then constitute ‘imaginative’ exercises of perceptual
concepts.[3]
The function of
the templates is to accumulate information about the relevant referents, and
thereby guide the subject’s future interactions with them. We can suppose that various items of
information about the referent will become attached to the template as a result
of the subject’s experience. When the perceptual
concept is activated, these items of information will be activated too. They may include features of the referent
displayed in previous encounters. Or
they may simply comprise behavioural information, in the form of practical
knowledge that certain responses are appropriate to the presence of the
referent. When the referent is
re-encountered, the subject will thus not only perceive it as presently located
at a certain position in egocentric space, but will also take it to possess
certain features that were manifested in previous encounters, but may not yet be
manifest in the re-encounter.
Imaginative exercises of perceptual concepts may further allow subjects
to process information about the referent even when it is not present.
Note how this
function of carrying information from one use to another highlights the
distinction between perceptual concepts and demonstratives. Demonstrative terms do not so carry a body of
information with them, for the obvious reason that they refer to different entities
on different occasions of use.
Information about an entity referred to by a demonstrative on one
occasion will not in general apply to whatever entity happens to be the
referent the next time the demonstrative is used. By contrast, perceptual concepts are suited
to serve as repositories of information precisely because they refer to the
same thing whenever they are exercised.
2.3 Perceptual Semantics
I have said that
perceptual concepts refer to perceptible entities. However, what exactly determines this
relation between perceptual concepts, conceived as stored sensory templates,
and their referents? In particular, what
determines whether such a concept refers to a type or a token? I suggested earlier that you might look at a
bird, form some stored sensory template, and then use it to think either
about that particular bird or about its species. But what decides between these two
referents? At first pass, it seems that
just the same sensory template might be pressed into either service.
Some philosophers
think of perceptual concepts as ‘recognitional concepts’ (Loar 1990). This terminology suggests that perceptual
concepts should be viewed as referring to whichever entities their possessors
would recognize as satisfying them. A
stored sensory template will refer to just that entity which will activate it
when encountered. If none but some
particular bird will activate some template, then that particular bird is the
referent. If any member of a bird
species will activate a template, then the species is the referent.
This recognitional
account would serve adequately for most of the further purposes of this
paper. But in fact it is a highly
unsatisfactory account of perceptual reference.
Now I have raised this topic, I would like to digress briefly and
explain how we can do better.
First, let me
briefly point out the flaws in the recognitional account. For a start, it’s not clear that
recognitional abilities are fine-grained enough to make the referential
distinctions we want. Could not two
people have just the same sensory template, and so be disposed to recognize
just the same instances, and yet one be thinking about a particular bird, and
the other about the species? It is not
obvious, to say the least, that my inability to discriminate perceptually
between the bird in my garden and its conspecifics means that I must be
thinking about the whole species rather than my particular bird; nor, conversely, is it obvious that I must be
thinking of my bird rather than its species if I mistakenly take some
idiosyncratic marking of my bird to be a characteristic of the species. In any case, the equation of referential
value with recognitional range faces the familiar problem that it seems to
exclude any possibility of misrecognition: if the referent of my perceptual concept is
that entity which includes all the items I recognize as satisfying the concept,
then there is no room left for me to misapply the concept perceptually. However, this isn’t what we want—far from
guaranteeing infallibility, perceptual concept possession seems consistent with
very limited recognitional abilities.
I think we will do
better to approach reference by focusing on the function of perceptual
concepts rather than their actual use.
As I explained in the last subsection, the point of perceptual concepts
is to accumulate information about certain entities and make it available for
future encounters. Given this, we can
think of the referential value of a perceptual concept as that entity which it
is its function to accumulate information about. Give or take a bit, this will depend on two
factors: the origin of the
perceptual concept, and the kind of information that gets attached to
it.
Let me take the
second factor first. Note that the kind
of information that it is appropriate to carry from one encounter to another
will vary, depending on what sort of entity is at issue.[4] For example, if I see that some bird has a
missing claw, then I should expect this to hold on other encounters with that
particular bird, but not across other encounters with members of that
species. By contrast, the information
that the bird eats seeds is appropriately carried over to other members of the
species. The point is that different
sorts of information are projectible across encounters with different types of
entity. If you are thinking about some
metal, you can project melting point from one sample to another, but not the shape
of the samples. If you are thinking
about some species of shellfish, you can project shape, but not size. If you are thinking about individual humans,
you can project ability to speak French, but not shirt colour. And so on.
Given this, we can
think of the referents of perceptual concepts as determined inter alia by what sort
of information the subject is disposed to attach to that concept. If the subject is disposed to attach
particular-bird-appropriate information, then the concept refers to a
particular bird, while if the subject is disposed to attach bird-species-appropriate
information, then reference is to a species.
In general, we can suppose that the concept refers to an instance of
that kind to which the sort of information accumulated is appropriate.
To make this
suggestion more graphic, we might think of the templates corresponding to perceptual
concepts as being manufactured with a range of ‘slots’ ready to be filled by certain
items of information. Thus a
particular-bird-concept will have slots for bodily injuries and other visible
abnormalities; a
particular-person-concept will have slots for languages spoken; a metal-concept will have a slot for melting
point; and so on. Which slots are present will then determine
which kind of entity is at issue.
The actual
referent will then generally be whichever instance of that kind was responsible
for originating the perceptual concept.
As a rule, we can suppose that the purpose of any perceptual concept is
to accumulate information about that item (of the relevant kind) that was
responsible for its formation. This
explains why there is a gap between referential value and recognitional
range. I may not be particularly good at
recognizing some entity. But if that
entity is the source of my concept, then the concept’s function is still to
accumulate information about it.
Of course, if some
perceptual concept comes to be regularly and systematically triggered by some
entity other than its original source, and as a result information derived from
this new entity comes to eclipse information about the original source, then no
doubt the concept should come to be counted as referring to the new entity
rather than the original source. But
this special case does not undermine the point that a perceptual concept will
normally refer to its origin, rather than to whichever entities we happen to recognize
as fitting it.
Now that I have
explained how it is possible for perceptual concepts to refer differentially to
both particular tokens and general types, some readers might be wondering how
things will work with subjects who have perceptual concepts both for some token
and its type—for example, suppose that I have a perceptual concept both for
some particular parrot and for its species.
To deal with cases like this, we need to think of perceptual concepts as
forming structured hierarchies. When
someone has perceptual concepts both for a token and its type, the former will
add perceptual detail to the latter, so to speak. The same will also apply when subjects have
concepts of some determinate (mallard,
say) of some determinable type (duck). In line with this, when some more detailed
perceptual concept is activated, then so will any more general perceptual
concepts which covers it, but not vice versa.
Since any items of information that attach to such more general concepts
will also apply to the more specific instances, this will work as it should,
giving us any generic information about the case at hand along with any
case-specific information.
Before proceeding,
let me make it clear how I am thinking about the relationship between
perceptual concepts and conscious perceptual experience. I want to equate conscious perceptual
experiences with the activation of perceptual concepts, due either to exogenous
stimulation or to endogenous imagination.
This does not necessarily mean that any activations of perceptual
concepts are conscious. There may be
states that fit the specifications of perceptual concepts given so far, but
whose activations are too low-level to constitute conscious states—early stages
of visual processing, say. My assumption will only be that there is some
range of perceptual concepts whose activations constitute conscious perceptual
experience.[5] In line with this, I shall restrict the term
‘perceptual experience’ to these cases—that is, I shall use ‘experience’ is a
way that implies consciousness. In
addition, I shall also assume that the phenomenology of these states goes with
the sensory templates involved, independently of what information the subject
attaches to those templates or is or is disposed to attach to them. (So if you and I use the same sensory pattern
to think about a particular bird and a bird species respectively, the
what-it’s-likeness of the resulting experiences will nevertheless be the same[6].)
2.4 Perceptually Derived Concepts
The discussion so
far has assumed that thoughts involving perceptual concepts will require the
subject actually to be perceiving or imagining.
In order for the perceptual concept to be deployed, the relevant stored
template needs either to be activated by a match with incoming stimuli, or to
be autonomously activated in imagination.[7]
However, now
consider this kind of case. You have
previously visually encountered some entity—a particular bird, let us
suppose—and have formed a perceptual concept of that bird. As before, you exercise this perceptual
concept when you perceive further birds as the same bird again, or when you
imagine the bird. However, now suppose
that you think about the bird when it is not present, and without imaginatively
recreating your earlier perception. You
simply think ‘That bird must nest near here’, say, without any accompanying
perceptual or imaginative act. I take it
that such thoughts are possible.[8] Having earlier established perceptual contact
with some entity, you can subsequently refer to it without the active help of
either perception or imagination. I
shall say that such references are made via perceptually derived concepts.
Here is one way to
think about this. Initially your
information about some referent was attached to a sensory template. But now you have further created some
non-perceptual ‘file’, in which your store of information about that entity is
now also housed. This now enables you to
think about the entity even when you are not perceiving or imagining it. When you later activate the file, you
automatically refer to the same entity as was referred to when the file was
originally created.[9]
Perhaps the
ability to create such non-perceptual files is peculiar to linguistic
creatures. This is not to say that any
such file must correspond to a term in a public language: you can think non-perceptually about things
for which you have no name—for example, you may have no name for the bird that
that you think nests nearby. Still, in
evolutionary terms it seems likely that the ability to think non-perceptually
depended on the emergence of language.
In this connection, note that an ability to think about things that you
have not perceived, and so cannot perceptually recognize or imagine, must play an essential part in
mastery of a public language. For public
languages are above all mechanisms that allow those who have first-hand
acquaintance with certain items of information to share that information with
others—which means that those who receive such information will often need to
create non-perceptual ‘files’ for entities they have never perceived
themselves. By contrast, languageless
creatures will have no channels through which to acquire information about
items beyond their perceptual ambit, and so no need to represent those items non-perceptually. This provides good reason to suppose that the
ability to create non-perceptual ‘files’ arrived only with the emergence of
language. If this is right, then only
language-using human beings will be able to transcend perceptual concepts proper
by constructing what I am calling ‘perceptually derived concepts’. Of course, as noted at the beginning of this
paragraph, humans will also sometimes use this ability to create non-perceptual
‘files’ that correspond to no word in a public language. But, still, when they do so, they may well be
drawing on an ability that evolved only along with linguistic capacities.
Perhaps there is
an issue about counting concepts here. I
have distinguished between ‘perceptual concepts’ and ‘perceptually derived concepts’. Do I therefore want to say that a thinker who
has constructed a ‘perceptually derived concept’ from a prior ‘perceptual
concept’ now has two concepts that refer to the same thing? From some perspectives, this might seem like
double counting. In particular, it is
not clear that the standard Fregean criterion of cognitive significance will
tell us that there are two concepts here.
After all, if the creation of a ‘perceptually derived concept’ is simply
a matter of housing your store of information in a non-perceptual file, as I
put it above, and if any subsequently acquired information about the relevant
referent automatically gets attached to both sensory template and
non-perceptual tag, then it seems that the subject will always make exactly the
same judgements whether using the ‘perceptual’ or ‘perceptually derived’
concept, and so fail the Frege test for possession of distinct concepts. And this would suggest that we simply have one
concept here, not two, albeit a concept which can be exercised in two
ways—perceptually and non-perceptually.[10]
There is no
substantial issue here. To the extent
that the flow of information between the two ways of thinking is smooth, the
Frege test gives us reason to say that there is only one concept. On the other hand, to the extent that there
are cognitive operations that distinguish a perceptually derived concept from
its originating perceptual concept, there is a rationale for speaking of two
concepts, and I shall do so when this is convenient.
3 Phenomenal
Concepts
3.1 The Quotational-Indexical Model
Let me now turn to
phenomenal concepts. My earlier
‘quotational-indexical’ model, recall, viewed phenomenal concepts as having the
structure the experience: —, where the gap was filled either an actual perceptual
experience or an imaginative recreation thereof. It now seems to me that this
‘quotational-indexical’ model ran together a good idea with a bad one. The good idea was to relate phenomenal
concepts to perceptual concepts. The bad
idea was to think that phenomenal concepts, along with perceptual ones, are
some kind of ‘demonstrative’.
Let me first explain
the bad idea. Suppose that perceptual
concepts were demonstrative, contrary to the argument of the last section. Then presumably they would be constructions
that, on each occasion of use, referred to whichever item in the external
environment was somehow salient to the subject.
By analogy, if phenomenal concepts worked similarly, then they too would
refer to salient items, but now in the ‘internal’ conscious environment. This thus led me to the idea that phenomenal
concepts were somehow akin to the mixed demonstrative construction that experience. On this model, phenomenal concepts would
employ the same general demonstrative construction (that) as is employed by ordinary mixed demonstratives, but the
qualifier experience would function
to direct reference inwards, so to speak, ensuring that some salient element is
the conscious realm is picked out. The
‘quotational’ suggestion then depended on the fact that this demonstrated
experience would itself be present in the realm of conscious thought, unlike
the non-mental items referred to by most demonstratives. This made it seem natural to view phenomenal
concepts as ‘quoting’ their referents, rather than simply referring to distal
items. Linguistic quotation marks, after
all, are a species of demonstrative construction: a use of quotation marks will refer to that
word, whatever it is, that happens to be made salient by being placed
within the quotation marks. Similarly, I
thought, phenomenal concepts can usefully be thought of as referring to that
experience, whatever it is, that is currently made salient in thought.
However, this now
seems to me all wrong. Not only is it
motivated by a mistaken view of perceptual concepts, but it runs into awkward
objections about the nature of the notion of experience used to form the putative construction that experience.
There seem two
possible models for the concept of experience
employed here. It might be abstracted
from more specific phenomenal concepts (seeing
something red, smelling roses,
and so on); alternatively, it could be
some kind of theoretical concept, constituted by its role in some theory
of experiences. However, neither option
seems acceptable.
The obvious
objection to the abstraction strategy is that it presupposes such specific
phenomenal concepts as seeing something
red, smelling roses, and so on,
when it is supposed to explain them. If
we are to acquire a generic concept of experience via first thinking phenomenally
about more specific experiences, and then abstracting a concept of what they
have in common, then it must be possible to think phenomenally about the more
specific experiences prior to developing the generic concept. But if thinking phenomenally about the more
specific experiences requires us already to have the generic concept, as on the
demonstrative account of phenomenal concepts, then we are caught in a circle.
What if our notion
of experience is constituted by its role in some theory of experiences (our folk
psychological theory perhaps)? Given
such a theoretically defined generic concept of experience, there would be no
barrier to then combining it with a general-purpose ‘that’ to form
demonstrative concepts of specific experiences.
Since the generic concept wouldn’t be derived by abstraction from prior phenomenal
concepts of specific experiences, there would be no circle in using it to form
such specific phenomenal concepts.
This picture may
be cogent in principle, but it seems to be belied by the nature of our actual
phenomenal concepts. If a generic
concept of ‘experience’ were drawn from something like folk psychological
theory, then we could expect it to involve some commitment to the assumption
that experiences are internal causes of behaviour. Folk psychology surely conceives of
experiences inter alia as internal states with characteristic causes and
behavioural effects. But then it would
seem to follow that anything demonstrated as that experience, where experience
is the folk psychological concept, must analytically have some behavioural
effects. It needn’t be analytic which
specific behavioural effects that
experience has—you could know that all experiences have characteristic
effects without knowing what specific effects that experience has—but still, it would be analytic that that experience had some
behavioural effects. However, this doesn’t
seem the right thing to say about phenomenal concepts. There is surely nothing immediately
contradictory in the idea that an experience picked out by some phenomenal
concept has no subsequent effects on
behaviour or anything else.
Epiphenomenalism about phenomenal states doesn’t seem to be a priori
contradictory.[11] Yet it would be, if our ways of referring to
phenomenal states analytically implied that they had behavioural effects.
3.2 Phenomenal Concepts as Perceptual Concepts
I said above that
my old model of phenomenal concepts ran together the good idea that phenomenal
concepts are related to perceptual concepts with the bad idea that both kinds
of concepts are ‘demonstratives’. Let me
now try to develop the good idea unencumbered by the bad one.
My current view is
that phenomenal concepts are simply special cases of perceptual concepts. Consider once more the example where I
perceptually identify some bird and make some judgement about it (THAT is a migrant). I earlier explained how the perceptual
concept employed here could either be a concept of an individual bird or the
concept of a species. I want now to suggest
that we think of phenomenal concepts as simply a further deployment of the same
sensory templates, but now being used to think about perceptual experiences
themselves, rather than about the objects of those experiences. I see a bird, or visually imagine a bird, but
now I think, not about that bird or a species, but about the experience, the
conscious awareness of a bird.[12]
The obvious
question is—what makes it the case that I am here thinking about an experience,
rather than an individual bird or a species?
However, we can give the same answer here as before. I earlier explained how the subject’s
dispositions to carry information from one encounter to another can decide
whether a given sensory template is referring to an individual rather than a
species, or vice versa—if the subject projects species-appropriate information,
reference is to a species, while if the subject projects individual-appropriate
information, reference is to an individual.
So let us apply the same idea once more—if the subject is disposed to
project experience-appropriate information from one encounter to
another, then the sensory template in question is being used to think about an
experience. For example, suppose I am
disposed to project, from one encounter to another, such facts as that what I
am encountering ceases when I close my eyes, goes fuzzy when I am tired, will
be more detailed if I go closer, and so on.
If this is how I am using the template as a repository of information,
then I will be referring to the visual experience of seeing the bird, rather
than the bird itself. More generally, if
they are used in this kind of way—to gather experience-appropriate information,
so to speak—the same sensory templates that are normally used to think about
perceptible things will refer to experiences themselves.
Can phenomenal
concepts pick out experiential particulars as well as types? In the perceptual case, as I have just
explained, there is room for such differential reference to both particular
objects and to types, due to the possibility of differing dispositions to carry
information from one encounter to another.
In principle it may seem that the same sort of thing could work in the
phenomenal case. The trouble, however,
is that particular experiences, by contrast with ordinary spatio-temporal
particulars, do not seem to persist over time in the way required for
re-encounters to be possible. Can the
same particular pain, or particular visual sensation, or particular
feeling of lassitude, re-occur after ceasing to be phenomenally present? It is true that we often say things like ‘Oh
dear, there’s that pain again—I thought I was rid of it’. But nothing demands that we read such remarks
as about quantitative rather than qualitative identity: nothing forces us to understand them as
saying that the same particular experience has re-emerged, as it were, rather
than that the same experiential type has been re-instantiated (note in
particular that experiences do not seem to allow anything analogous to the
spatio-temporal tracking of ordinary physical objects). In line with this, note that information
about experiences, as opposed to information about spatio-temporal particulars,
does not seem to divide into items that are projectible across encounters with
a particular and items that are projectible across encounters with a type.
Given all this, I
am inclined to say that phenomenal concepts cannot refer differentially both to
particulars and to types. Rather they
always refer to types—that is, to the kind of mental item that can clearly
re-occur. As I am conceiving of
perceptual and phenomenal concepts, the function of a concept is to carry
information about its referent from one encounter to another—and it seems that
only phenomenal types and not particulars can be re-countered.
The corollary is
that, when we do refer to particular experiences, we cannot be using our basic
apparatus of phenomenal concepts, given that these are only capable of
referring to phenomenal types. Rather,
we must be invoking more sophisticated conceptual powers, such as the ability
to refer by description (thus the
particular pain I am having now, or the
particular experience of crimson I enjoyed at last night’s sunset).
3.3 Phenomenal Use and Mention
This model of
phenomenal concepts as a species of perceptual concept retains one crucial
feature from my earlier quotational-indexical model, namely, that phenomenal references
to an experience will involve an instance of that experience, and in this sense
will use that experience in order to mention it.
To see why, think
about what happens when a phenomenal concept is exercised. Some sensory template is activated, and is
used to think about an experience. This
sensory activation will either be due to externally generated sensory stimuli
or to autonomous imaginative activity.
That is, you will either be perceiving the environment, or employing
perceptual imagination. For example,
either you will be perceiving a bird, or you will be perceptually imagining
one. Except, when phenomenal thought is
involved, this template is also used to think about perceptual experience,
rather than just about the objects of perceptions. You look at a bird, or visually imagine that
bird, but now use the sensory state to think about the visual experience of
seeing the bird, and not only about the bird itself.
This means that
that any exercise of a phenomenal concept to think about a perceptual
experience will inevitably either involve that experience itself or an
imaginary recreation of that experience.
If we count imaginary recreations as ‘versions’ of the experience being
imagined, then we can say that phenomenal thinking about a given experience
will always use a version of that experience in order to mention
that experience.
Note how this
model accounts for the oft-remarked ‘transparency of experience’ (Harman 1990). If we try to focus our minds on the nature of
our conscious experiences, all that happens is that we focus harder on the
objects of those experiences. I try to
concentrate on my visual experience of the bird, but all that happens is that I
look harder at the bird itself. Now,
there is much debate about exactly what this implies for the nature of
conscious experience (cf. Stoljar, forthcoming). But we can by-pass this debate here, and simply
attend to the basic phenomenon, which I take to be the phenomenological equivalence
of (a) thinking phenomenally about an experience and (b) thinking
perceptually with that experience.
What it’s like to focus phenomenally on your visual experience of the
bird is no different from what it’s like to see the bird.
On my model of
phenomenal thinking, this is just what we should expect. I said at the end of the last section that
the phenomenology of perceptual experiences is determined by which sensory template
they involve, and not by what information they carry with them. I have now argued that just the same sensory
templates underly both perceptual experiences and phenomenal thoughts about
those experiences. It follows that
perceptual experiences and phenomenal thoughts about them will have just the
same phenomenology. This explains why
thinking phenomenally about your visual experience of a bird feels no different
from thinking perceptually about the bird itself.
3.4 A Surprising Implication
The story I have
told so far has an implication that some might find surprising. On my account, the semantic powers of
phenomenal concepts would seem to depend on their cognitive function, rather
than their phenomenal nature. I have
argued that phenomenal concepts refer to conscious experiences because it is
their purpose to accumulate information about those experience. As it happens, exercises of such concepts
will in part be constituted by versions of the conscious experiences they refer
to, and so will share the ‘what-it’s-likeness’ of those experiences. But this latter, phenomenal fact seems to
play no essential role in the semantic workings of phenomenal concepts. To see this, suppose that we had evolved to
attach information about conscious experiences to states other than sensory
templates—to words in some language of thought, perhaps. Wouldn’t these states
refer equally to experiences, and for just the same reason, even though their
activation did not share the phenomenology of their referents? However, this might seem in tension with the
idea that phenomenal concepts involve some distinctive mode of phenomenal self-reference
to experiences. If the phenomenality of
phenomenal concepts is incidental to their referential powers, then in what
sense are they distinctively phenomenal?
(Cf. Block, forthcoming.)
Note that my
earlier ‘quotational-indexical’ account of phenomenal concepts is not open to
this kind of worry. On that account,
phenomenal concepts used experiences as exemplars, rather than as ways
of implementing a cognitive role. Given
this, it is essential to the phenomenal concept of seeing something red, say, that ‘quotes’ some version of that
experience, just as it is essential to the quotational referring expression ‘
“zymurgy” ’ that it contain the last word in the English dictionary within the
inner quotation marks. On the
quotational-indexical account then, there is no question of some state
referring to an experience in the same way as a phenomenal concept does, yet
its exercise not involve the experience.
Note also that the
worrisome implication is not peculiar to the particular theory of the semantics
of phenomenal concepts I have defended in this paper. It will arise on any theory that makes the
semantic powers of phenomenal concepts a matter of their conceptual role, or
their informational links to the external world, or any other facet of their
causal-historical workings. For any
theory of this kind will make it incidental to the referential powers of
phenomenal concepts that they have the same phenomenology as their referents. Any such theory leaves it open that some
other states, with different or no phenomenology, could have the same
causal-historical features, and so refer to experiences for the same reason
that phenomenal concepts do.
My response to
this worry is that there is no real problem here. On my account, it is indeed true that
phenomenal concepts refer because of their cognitive function, not because of
their phenomenology, and therefore that other states with different or no phenomenology,
but with the same cognitive function, would refer to the same experiences for
the same reasons. I see nothing wrong
with this. Of course, it is a further
question whether we would wish to include any such non-phenomenological states
within the category of ‘phenomenal’ concepts, given their lack of
what-it’s-likeness (cf. Tye 2003). But
this is no grounds for denying that they would refer to experiences for just
the same reason as phenomenal concepts do.
I shall come back
to the issue of what counts as a ‘phenomenal’ concept in the next section. But first let me ask a somewhat different
question. Given that other items could
in principle play the cognitive role that determines reference to experiences, why
do we use experiences themselves for this purpose? What is it about conscious experiences that
makes them such a good vehicle for referring to themselves?
One possible
answer is that this use of experiences is somehow well-suited to answering
certain questions. To adapt an example
of Michael Tye’s (2003, p. 102), suppose that we are wondering whether the
This makes some
sense, but I think a simpler answer may be possible. Consider the analogous question: why do we use perceptual experience to
represent perceptible items such as people, physical objects, animals, plants,
shapes, colours, and so on? After all,
in this case too the referential powers of these states are presumably
determined by some type of cognitive role, which could in principle have been
played by something other than perceptual experiences themselves. Here the obvious answer seems to be that the
perceptions are especially good for thinking about perceptible entities simply
because they are characteristically activated by those entities, and so are
well-suited to feature in judgements that those entities are present. It would unnecessarily duplicate cognitive
mechanisms to use the perceptual system to identify perceptible entities, yet
something other than perceptual experiences as the vehicle for occurrent thoughts
that imply that those entities are present.
This thought
applies all the more in the phenomenal case.
Conscious experiences are excellent vehicles for thinking about those
selfsame experiences, simply because they are automatically present whenever
their referents are. The fact that we
use experiences to think about themselves means that we don’t have to find
other cognitive resources to frame occurrent thoughts about the presence of
experiences.
4. Phenomenal Concepts and Anti-Materialist
Arguments
4.1 The Knowledge Argument
In the last subsection
I raised the issue of what exactly qualifies a concept as ‘phenomenal’. I have no definite answer to this
definitional question. Far more
important, from my point of view, is whether phenomenal concepts as introduced
so far provide effective answers to the standard anti-physicalist
arguments. I shall now aim to show that
they do this. In the course of doing so,
however, I shall highlight those features of phenomenal concepts that are important
to their serving this philosophical function.
We can leave it open which features of phenomenal concepts are essential
to their counting as ‘phenomenal’. But
it is worth being clear about which features matter to the philosophical
arguments.
Let me begin with
Frank Jackson’s knowledge argument. Here
the Type-B physicalist response is that there is indeed a sense in which Mary
doesn’t ‘know what seeing red is like’ before she comes out of her room,
despite her voluminous material knowledge.
But this is not because there is any objective feature of reality that
her material knowledge fails to capture, but simply because there is a way of
thinking about the experience of seeing red that is unavailable to her
while still in the room. Before she
comes out of the room, she lacks a phenomenal concept of the experience of
seeing red. She could always think about
the experience using her old material concepts all right, but not with any
phenomenal concept. This is why she did
not know that seeing red =THAT experience
(where this is to be understood as using a material concept on the left-hand
side and a phenomenal concept on the right-hand side).
The crucial
feature of phenomenal concepts, for the purposes of this argument, is that they
are experience-dependent: the
concept’s acquisition depends on its possessor having previously undergone the
experience it refers to. This is why she
doesn’t ‘know what seeing red is like’ before she comes out of the room. She needs to see red in order to acquire the
conceptual wherewithal to think seeing
red = THAT experience.
The reason that
Mary’s new concept is experience-dependent is that it requires a sensory
template, and her acquisition of this template depends on her visual system
having previously been activated by some red surface. This is of course a contingent feature of
human beings. We can imagine beings who
are born with the sensory templates that we acquire from colour experiences (cf.
Papineau 2002 section 2.8). Still, as it
happens, humans are not like this. They
are born with few, if any, sensory templates, but must rather acquire them from
previous experiences. (If humans were
born with the sensory templates activated by red surfaces, then physicalists
could not answer the knowledge argument by saying that Mary needs a red
experience in order to acquire a phenomenal concept of red. But if humans were like that, then
physicalists wouldn’t need to answer the knowledge argument in the first place,
since Mary would already have a phenomenal concept of red before she left her
room, and so would already be in a position to know that seeing red = THAT experience, by courtesy of an imaginative
exercise of her phenomenal concept on the right-hand side.)
4.2 I am
not now having or imagining THAT experience
It is worth distinguishing
the experience-dependence of phenomenal concepts from the use-mention feature
discussed in subsection 3.3 above. Even
though normal examples of phenomenal concepts, like the one Mary acquires on
leaving her room, have both the experience-dependence and use-mention features,
there is space in principle for concepts which are phenomenal in the sense of
being experience-dependent but which don’t use experiences to mention themselves. Indeed, I would argue that this is not just
an abstract possibility—there are actual concepts which display experience-dependence,
but not the use-mention feature.
To see why, recall
the earlier discussion of perceptually derived concepts. These derived concepts involved the creation
of some non-sensory file to house the information associated with some
perceptual concept, and they made it possible to think about perceptible entities
even when those entities were not being perceived or perceptually imagined. Analogously, we can posit a species of
‘phenomenally derived concept’. Suppose
someone starts off, like Mary, by thinking phenomenally using a sensory
template instilled by previous experiences.
But then she creates a non-sensory file in which to house the
information that has become attached to that template, and which will henceforth
allow her to think about the experience without any sensory activation. I say she now has a phenomenally derived
concept. Exercises of this concept won’t
activate the experience it mentions, and so this concept will fail to satisfy
the use-mention requirement. But this
phenomenally derived concept will still satisfy the experience-dependence
requirement, in that its creation depends on a prior phenomenal concept which
in turn depends on previous experiences.
The possibility of
phenomenally derived concepts offers an answer to an objection raised in the
Introduction. This was that standard
accounts of phenomenal concepts seem to imply that any exercise of a phenomenal
concept demands the presence of the experience it refers to or an imaginatively
recreated exemplar thereof. However,
this seems too demanding. Surely someone
like Mary can use her new concept to think truly that I am not now having THAT experience (nor recreating it in my
imagination). Yet this should be
impossible, if any exercise of her phenomenal concept does indeed require the
relevant experience or its imaginative recreation.
My response to
this objection is that Mary thinks the problematic thought with the help of a phenomenally
derived concept.[13] She starts with a phenomenal concept based on
some sensory template, and then creates a non-sensory file to carry the
information associated with the template.
This allows her to think about the relevant experience without
activating the associated sensory template—that is, without either having or
imaginatively recreating the experience in question. She thinks I am not now having or imagining THAT experience—and since she is
using a phenomenally derived concept, what she thinks can well be true.
Some readers might
wonder whether it is really appropriate to say that Mary is here exercising a phenomenal
concept. After all, if this concept is
realized non-sensorily, then why is it any more ‘phenomenal’ that the general
run of ordinary concepts? In particular,
would we want to say that someone knows ‘what it is like’ to see something red,
merely in virtue of thinking seeing red =
THAT experience, where the right hand side deploys a phenomenally derived
concept, and so does not require the thinker actually to have the relevant
experience or its imaginative recreation?
Well, I have no principled
objection if someone wants to withhold the description ‘phenomenal’ on these
grounds. But note that this move is not
available to someone who wants to press the objection at hand, which after all
is precisely that there seems room for a thinker to exercise a ‘phenomenal’
concept while not having any version of the experience referred to. For this objection to make any sense,
‘phenomenal’ cannot be understood as requiring sensory realization per se. Rather, it has to be understood simply as
standing for those concepts whose acquisition depends on undergoing the
relevant experience. And in this sense
of ‘phenomenal’—experience-dependence—phenomenally derived concepts do explain
how someone can think phenomenally without having any version of the
corresponding experience. For phenomenally
derived concepts are certainly experience-dependent, given that they derive
from phenomenal concepts that derive from prior experiences.
4.3 Semantic Stability and A Posteriori Necessity
Let me now turn to
anti-materialist arguments which turn on modal considerations. The best know of these is Kripke’s argument
against the identity theory in Naming and Necessity (1980). But before addressing this, I would like to
consider a different modal argument, which I shall call ‘the argument from
semantic stability’. As it turns out,
both these arguments can be blocked by appealing to the use-mention feature of
phenomenal concepts. But the way this
works is rather different in the two cases.
The argument from
semantic stability hinges on the fact that Type-B physicalists take identity
claims like nociceptive-specific neuronal
activity = pain (where the right hand side uses a phenomenal concept) to be
a posteriori necessities. The
distinctness of the concepts on either side of the identity claim means that
there is no question of knowing such claims a priori. Even after she had acquired both concepts,
Mary still needs empirical information to find out that pain was the same experience as nociceptive-specific
neuronal activity. In this respect,
Type-B physicalists take mind-brain identity claims to be akin to such familiar
a posteriori necessities as water = H2O,
lightning = electric discharge, or Hesperus = Phosphorous.
The objection to Type-B
physicalism is then that phenomenal mind-brain identities cannot possibly be
akin to these familiar a posteriori necessities, because a posteriori necessity
is characteristically due to ‘semantic instability’, but phenomenal concepts
are semantically stable.[14]
Let me unpack this. Note first that, in all the examples of
familiar a posteriori necessities listed above, the referential value of at
least one of the concepts involved—water,
lightning, Hesperus (and indeed Phosphorus)—depends,
so to speak, on how things actually are.
If it had turned out that XYZ and not H2O is the colourless
liquid in rivers, etc, then water
would have referred to XYZ. If it had
turned out that some heavenly body other than Venus is seen in the early
morning sky, then Hesperus would have
referred to that other heavenly body.
And so on.
This observation
suggests the hypothesis that a priority and necessity only come apart in the
presence of semantically unstable concepts.
On this hypothesis, claims formulated using semantically stable concepts will be necessary if and
only if they are a priori. Certainly
there are plenty of concepts that seem to be stable in the relevant sense, that
is, whose referents seem not to be actual-fact-dependent. Physical concepts like electron or H2O
seem to be like this, as do such everyday concepts like garden or baseball. And if we stick to claims involving only such
stable concepts (electrons are negatively
charged, say, or baseball is a game)
then it does seem plausible that these claims will be necessary if and only if
they are a priori.
The general idea
here is that necessities will only be a posteriori when you are ignorant of the
essential nature of some entity you are thinking about. If your concepts are transparent to you, if
their real essence coincides with their nominal essence, so to speak, then you
will be able to tell a priori whether claims involving them are necessary or
not. But with semantically unstable
concepts we need empirical information to know what they refer to, and so to
ascertain whether a necessary proposition is expressed. To take just the first example above, it
takes empirical work to discover that H2O is the referent of water, and so that water = H2O is necessarily true.
The claim is thus that
a posteriori necessity always turns on the presence of concepts whose reference
is actual-fact-dependent; correlatively,
if we keep away from such concepts, then necessity and a priority will always
go hand in hand.
If this claim is
accepted, then it is indeed hard to see how phenomenal mind-brain identity
claims like pain = nociceptive-specific
neuronal activity could be a posteriori necessities. For the phenomenal concepts like pain do not seem to be
semantically unstable. There seems little
sense to the idea that it could have turned out, given different empirical
discoveries, that pain referred to
something other than its actual referent.
But then, given
the general thesis that a posteriori necessity requires semantic instability,
it follows that nociceptive-specific
neuronal activity = pain cannot
be an a posteriori necessity. Since we
don’t need any empirical information to know what pain refers to, we must already know what proposition the claim nociceptive-specific neuronal activity =
pain expresses, just in virtue of our grasp of the concept pain, and so ought to be able to tell a
priori that this claim is true, if it is.
But we can’t, so it can’t be true.
In the face of
this argument, Type-B physicalists need to deny that a posteriori necessities
require semantically unstable concepts. There
seems no doubt that phenomenal concepts are semantically stable. And it is constitutive of Type-B physicalism
that phenomenal mind-brain identities are a posteriori. So the only option left is to insist that
these identities are a posteriori necessities which involve no semantic
instability.
Opponents will ask
whether phenomenal mind-brain identities are the only such cases. If they are, then the Type-B physicalist move
can be charged with unacceptable ad hocness.
Type-B physicalists would seem to be guilty of special pleading, if the
connection between a posteriori necessity and semantic instability holds good
across the board, excepting only those cases where phenomenal concepts are involved.
One obvious way
for Type-B physicalists to respond to this charge of ad hocness is to seek
other examples of a posteriori necessities that do not involve semantic
instability. Obvious possibilities are
identities involving proper name concepts that (unlike Hesperus or Phosphorous)
do not have their references fixed by salient descriptions (Cicero = Tully , say) or again
identities involving perceptual concepts (such as reflectance profile Φ = red, where the right hand side uses a
perceptual colour concept).
However, opponents
of Type-B physicalism will deny that these a posteriori necessities are free of
semantic instability. Maybe the concepts
involved don’t have their references fixed by salient descriptions. But they will insist that this is not the
only way for concepts to be semantically unstable, and that more careful
analyses of semantic stability will show that proper name and perceptual
concepts are indeed unstable, while phenomenal concept are not, and are thus still
anomalous among concepts that enter into a posteriori necessities.[15]
I remain to be
persuaded about this charge of anomalousness.
However, I shall not dig my heels in at this point. Rather let me concede, for the sake of the
argument, that phenomenal mind-brain identities are indeed anomalous in not
involving any semantically unstable concepts.
I don’t accept that this means that these identities cannot be
true. Rather, I say that phenomenal
mind-brain identities are anomalous because phenomenal concepts are very peculiar. More specifically, phenomenal concepts have
the very peculiar feature of using the experiences they refer to. When we reflect on this, we will see that it
is unsurprising that identities involving phenomenal concepts should be unusual
in combining semantic stability with a posteriori necessity.
The underlying
anti-physicalist thought, recall, was that semantic stability goes hand in hand
with knowledge of real essences;
conversely, if thinkers are ignorant of real essences, they must be
using unstable concepts. The complaint
about Type-B physicalism, then, is that it requires the possessors of
phenomenal concepts like pain to be
ignorant of the real physical essence of pain, even though the concept pain is manifestly stable. The anti-physicalists thence conclude that pain must refer to something
non-physical, something with which the possessors of the concept are indeed
directly acquainted.
But Type-B
physicalists can respond that, however it is with other concepts, this combination
of semantic stability with ignorance of essence is just what we should expect
given the use-mention feature characteristic of phenomenal concepts. Even if phenomenal concepts don’t involve
direct knowledge of real essences, they will still come out semantically
stable, for the simple reason that the use-mention feature lead us to think of
the referent as ‘built into’ the concept itself. Since the concept uses the phenomenal
property it mentions, this alone seems to eliminate any conceptual or metaphysical
space wherein that concept might have
referred to something different.
Above I said that I
remained to be persuaded that phenomenal concepts are distinguished from proper
name and perceptual concepts in uniquely displaying this combination of
semantic stability and ignorance of essence.
Still, at an intuitive level we can see why phenomenal concepts should
appear special in this way. When we
think of proper name concepts like
In a sense,
phenomenal concepts are too close to their referents for it to seem possible
that those same concepts could refer to something else. With other concepts that enter into a
posteriori identities, including proper name and perceptual concepts, we can imagine
the ‘outside world’ turning out in such a way that they referred to something
other than their actual referents. Some
other person might have turned out be the historical source of my
If this is right,
then the semantic stability of phenomenal concepts provides no reason to think
that they must refer to non-physical properties with which their possessors are
directly acquainted. For the use-mention
feature of phenomenal concepts yields an independent explanation of why they
should be semantically stable, even while their possessors remain ignorant of
the real physical essences of their referents.
4.5 Kripke’s Original Argument
Let me now turn to
Saul Kripke’s original argument against the mind-brain identity theory. There are significant differences between
this and the argument from semantic stability.
Kripke doesn’t seem to be committed to the thesis that necessity only
comes apart from a priority in the presence of semantic instability. Kripke’s paradigm cases of a posteriori
necessities involve names whose reference is determined in line with his causal
theory of reference (Cicero = Tully),
and there is nothing in Kripke to suggest that this a posteriority demands that
the referential values of these names must be actual-fact-dependent. From a Kripkean point of view, there is
nothing special here that needs explaining—a posteriori necessities are simply
the natural consequence of the non-descriptive way reference is determined for
normal names.
Kripke’s argument
hinges not on the a posteriority of the physicalist’s identity
claims, but on their apparent contingency. Kripke has no complaint about the a posteriority
of claims like pain =
nociceptive-specific neuronal activity—a posteriori necessities are par for
the course, from a Kripkean point of view.
What Kripke takes to be problematic about these mind-brain identities,
rather, is that it seems that they might have been false: intuitively we feel that there are possible
worlds—zombie worlds, say—where nociceptive-specific neuronal activity is not
identical to pain. Now, there is nothing
per se incoherent in the idea of a necessary identity that appears
contingent. For example, we can make
sense of the idea that Hesperus = Venus
might have been false, by construing this identity claim as saying that the
heavenly body that appears in the morning is Venus—something which might well
have been otherwise. But now—and this is
Kripke’s point—this way of explaining the appearance of contingency does
require you to construe the relevant referring term as semantically unstable,
for it demands that you read the term in a way that makes it come out referring
to something different if the actual facts are different. Yet pain
cannot be read in such a way, which means, say Kripke, that the physicalist has
no satisfactory way of explaining the apparent contingency of phenomenal
mind-brain identities.
So Kripke gets to
the same place as the argument from semantic stability, but from a different
starting point. However, the differences
between the two arguments mean that Kripke’s argument demands a rather different
response from the physicalist. It is no
good to reply to Kripke that a posteriori necessity is consistent with semantic
stability, for he agrees about this, and indeed will allow that there are non-phenomenal
examples of this combination (Cicero = Tully). What he insists on, however, and this is a
different point, in that apparently contingency is inconsistent
with semantic stability, and that physicalists therefore have no way of
explaining the apparent contingency of mind-brain identities.
In response to the
argument for semantic stability, I denied that a posteriori necessity required semantic
instability, at least where mind-brain identities are involved. However, I don’t think that there is any
corresponding room to deny that apparent contingency must involve semantic
instability. If a claim can be
understood as actually true yet possibly false, then some of the concepts
involved must shift reference. Given
that the concepts in phenomenal mind-brain identity claims are all semantically
stable, this leaves the physicalist with one option—deny that phenomenal
mind-brain identities are apparently contingent.
This might seem
all wrong—isn’t it agreed on all sides that we can cogently conceive of zombies
(even if they aren’t really possible), and therewith that mind-brain identities
at least seem possibly false? So
what room is there for the physicalist to deny that mind-brain identities are
apparently contingent?
Well, I agree that
physicalists are compelled to allow that phenomenal mind-brain identities seem
possibly false. But this isn’t yet to
allow that they seem contingent.
Contingency requires not only falsity in some possible worlds, but also
truth in the actual world. And it is
specifically this combination that generates the need for semantic instability,
to give a non-actual referent that falsifies the claim in some possible
world. But there is another way for an
identity claim to seem possibly false—namely, for it simply to seem false. And in that case there is nothing to require semantic
instability.
Let me go more
slowly. Consider people who think that
So my suggestion
is that physicalists should say that mind-brain identities strike us just like Cicero = Tully strikes people who think
4.5 The Intuition of Distinctness
Some readers might
be wondering why the last subsection hasn’t conceded the anti-physicalist case
to Kripke. My suggestion is that
physicalists should explain our attitude to the possibility of zombies by
allowing that mind-brain identity claims strike us as false. But isn’t this tantamount to denying
physicalism?
Not necessarily. I say physicalists should allow that
physicalism seems false, not allow that it is false. That is, physicalists should maintain that we
have an intuition of mind-brain distinctness, but that this intuition is
mistaken.
This is by no
means ad hoc. It seems undeniable that
most people have a strong intuition of mind-brain distinctness—an intuition
that pains are something extra to brain states, say. This intuition is prior to any philosophical
analyses of the mind-brain relation, and indeed persists even among those (like
myself) who are persuaded by those analyses that dualism must be false. Given this, it is a requirement on any
satisfactory physicalist position that it offer some explanation of why we
should all have such a persistent intuition of mind-brain distinctness, even
though it is false. Physicalists need to
recognize and accommodate the intuition of distinctness, quite apart from
requiring it to deal with Kripke’s argument.
There are a number
of possible ways of explaining away the intuition of distinctness, especially
for physicalists who recognize phenomenal concepts. I myself favour an explanation that hinges on
the use-mention feature of phenomenal concepts, and which elsewhere I have
called ‘the antipathetic fallacy’.[20]
Suppose you entertain
a standard phenomenal mind-brain identity claim like pain = nociceptive-specific neuronal activity, deploying a phenomenal
concept on the left-hand side and a material concept on the right. Given that
the phenomenal concept uses the experience it mentions, your exercise of
this concept will depend on your actually having a pain, or an imagined
recreation thereof. Because of this,
exercising a phenomenal concept will feel like having the experience
itself. The activity of thinking
phenomenally about pain will introspectively strike you as involving a
version of the experience itself.
Things are different with the exercise of the
material concept on the right-hand side.
There is no analogous phenomenology.
Thinking of nociceptive-specific neuronal activity doesn't require any
pain-like feeling. So there is a
intuitive sense in which the exercise of this material concept ‘leaves out’ the
experience at issue. It ‘leaves out’ the
pain in the sense that it doesn't activate any version of it.
Now, it is all too easy to slide from this to
the conclusion that, in exercising such a material concept, we are not thinking
about the experiences themselves. After all, doesn't this material mode
of thought ‘leave out’ the experiences, in a way that the phenomenal concept does
not? And doesn't this show that the material concept simply doesn't refer to
the experience denoted by our phenomenal concept of pain?
This line of thought is terribly natural.
(Consider the standard rhetorical ploy: ‘How could pain arise from mere
neuronal activity?’) But of course it is
a fallacy. There is a sense in which material
concepts do ‘leave out’ the feelings. Uses of them do not in any way activate
the experiences in question, by contrast with uses of phenomenal concepts. But
it simply does not follow that these material concepts "leave out"
the feelings in the sense of failing to refer to them. They can still refer to
the feelings, even though they don't activate them.
After all, most concepts don't use or involve
the things they refer to. When I think of being rich, say, or having measles,
this doesn't in any sense make me rich or give me measles. In using the
states they refer to, pheneomenal concepts are very much the exception. So we
shouldn't conclude on this account that materialal concepts, which work in the
normal way of most concepts, in not using the states they refer to, fail to
refer to those states.
Still, fallacious
as it is, this line of thought still seems to me to offer a natural account of
the intuitive resistance to physicalism about conscious experiences. This
resistance arises because we have a special way of thinking about our conscious
experiences, namely, by using phenomenal concepts. We can think about our
conscious experience using concepts to which they which bear a phenomenal
resemblance. And this then creates the fallacious impression that other
non-phenomenal ways of thinking about those experiences fail to refer to the
felt experiences themselves.[21]
5 Chalmers on
Type-B Physicalism
5.1 Chalmers’ Dilemma
David Chalmers has
recently mounted an attack on the whole Type-B physicalist strategy of invoking
phenomenal concepts in order explain the mind-brain relation (Chalmers 2006—his
contribution to this volume). He aims to
present Type-B physicalists with a dilemma.
Let C be the thesis that humans possess phenomenal concepts. As Chalmers sees it, Type-B physicalists
require both (a) that C explains our epistemic situation with respect to
consciousness and (b) that C is explicable in physical terms. However, Chalmers argues that there is no
version of C that satisfies both these desiderata—either C can be understood in
a way that makes it physically explicable, or in a way that allows as to
explain our epistemic situation, but not both.
In order to
develop the horns of this dilemma, Chalmers asks the physicalist whether or not
C is conceptually guaranteed by the complete physical truth about the universe,
P. That is, is P and not-C conceivable?
Suppose the
physicalist says that this combination is conceivable. This makes the existence of phenomenal
concepts conceptually independent of all physical claims. But then, argues Chalmers, all the original puzzles
about the relation between the brain and phenomenal states will simply reappear
as puzzles about the relation between the brain and phenomenal concepts
themselves. So Chalmers holds that on
this option C fails to be physically explicable.
The other option
is for the physicalist to say that P and not-C is not conceivable. On this horn, claims about phenomenal
concepts will not be conceptually independent of P (suppose that
phenomenal concepts are conceived physically or functionally, say). However, this would mean that zombies (conceivable
beings who are physically identical to us but lack consciousness) would be
conceived as having phenomenal concepts.
However, argues Chalmers, we don’t conceive of zombies as epistemically related
to consciousness as we are (after all, they are conceived as not having any
consciousness). This argues that something
more than C is needed to explain our peculiar relation to consciousness. So Chalmers hold that on this option C fails
to explain our epistemic situation.
So—either P and
not-C is conceivable, or it isn’t. And on
neither option, argues Chalmers, is C both physically explicable and
explanatory of our epistemic situation.
5.2 The Dilemma Embraced
Far from viewing
Chalmers as offering a nasty choice, I am happy to embrace both horns of his
dilemma. I say that we can conceive of
phenomenal concepts in a way that makes them conceptually independent of the
physical facts, and also conceive them in a way that doesn’t make them so
independent. Moreover, I think that both
these ways of thinking about phenomenal concepts allows phenomenal concepts to
be simultaneously physically explicable and explanatory of our epistemic
situation.
It is the
use-mention feature of phenomenal concepts that allows them to be thought of in
two different ways. Exercises of
phenomenal concepts involve versions of the phenomenal states they refer
to. Given this, thinking about
phenomenal concepts requires us to think of the phenomenal states that they
use. But according to Type-B
physicalism, these used phenomenal states, like phenomenal states in general,
can be thought of in two different ways—phenomenally and non-phenomenally. So we can think about (first-order) phenomenal
concepts phenomenally, using (second-order) phenomenal concepts to think about
the phenomenal states involved, or we can think about them non-phenomenally, thinking
about the involved phenomenal states in physical or functional terms, say. Since the (second-order) phenomenal concepts
used on the first option, like all phenomenal concepts, will be a priori
distinct from any physical or functional concepts, the first way of thinking
about (first-order) phenomenal concepts will make P and not-C conceivable,
while the second way of thinking about (first-order) phenomenal concepts, as
physical or functional, will make P and not-C inconceivable.[22]
However, for a
Type-B physicalist, these two ways of thinking still refer to the same
entities—(first-order) phenomenal concepts.
And these entities will have the same nature and cognitive role, however
they are referred to. So the way they
are referred to ought to make no difference to whether they are physically
explicable and explanatory of our epistemic situation. They should satisfy these two desiderata
however they are referred to. Let me now
show that they do.
5.3 The First Horn
On the first horn,
we think about (first-order) phenomenal concepts by using further (second-order)
phenomenal concepts. That is, we note
that exercises of (first-order) phenomenal concepts involve uses of phenomenal
states, and when we think of the phenomenal states thus involved, we do so
using further (second-order) phenomenal concepts.
The problem on
this horn, according to Chalmers, relates to the epistemic and explanatory gap
between physical and phenomenal claims.
Chalmers views this gap as making a strong case for dualism, a case
which Type-B physicalists seek to block by showing that the existence of this
‘distinctive gap can be explained in terms of certain distinctive features of
phenomenal concepts’ (p. 00). However,
even if invoking phenomenal concepts can so succeed in explaining the original
gap between physical and phenomenal claims, Chalmers argues that physicalists
will now need to explain away a new gap between physical claims and claims
about the possession of phenomenal concepts—for, after all, on this horn of the
dilemma they agree that P and not-C is conceivable, that is, that the physical
facts do not conceptually necessitate claims about (first-order) phenomenal
concepts.
The natural
physicalist response is to argue that they can explain this new gap in just the
way that they explained the original one.
If we are conceiving of (first-order) phenomenal concepts using further
(second-order) phenomenal concepts, then of course there will be a conceptual
gap between physical claims and claims about phenomenal concepts. Still, if the original gap could be
‘explained in terms of certain distinctive features of [first-order] phenomenal
concepts’, as Chalmers is allowing for the sake of the argument, why can’t the
new gap be explained in terms of the same features of (second-order) phenomenal
concepts?
Chalmers objects
that this explanation-repeating move will be either regressive or circular (p.
00). But it is not obvious to me why
this should be so. In particular, there
doesn’t seem to be anything regressive or circular in repeating the explanatory
use that I myself have made of phenomenal concepts, as I shall show in a moment.
I suspect that
Chalmers’ charge of regression or circularity reflects the very high demands he
is placing on Type-B explanations of the conceptual gap. For the most part he leaves it open how such
explanations might go, being happy to conduct his argument on an abstract level. But just before his charge of regression or
circularity, he does propose one possible explanation of the original gap, suggesting
that Type-B physicalists might say that phenomenal concepts give their
possessors a distinctive kind of direct acquaintance with their referents, of a
kind that ‘one would not predict from just the physical/functional structure of
the brain’ (p. 00). Now, I agree that this
kind of explanation is going to get Type-B physicalists into trouble—though not
especially because it becomes regressive or circular when it is repeated at the
higher level, but simply because it is unacceptable to start with for a physicalist
to posit distinctive semantic powers of direct reference that correspond to
nothing identifiable in physical or functional terms.
Still, this
doesn’t mean that any Type-B physicalist explanation of the conceptual
gap is going to run into trouble. There
is no question here of cataloguing all the different ways in which different Type-B
physicalists have appealed to phenomenal concepts in order to account for
various ‘gaps’. Let me simply remind
readers of some of the things I said earlier, and show that there is nothing
regressive or circular about saying the same things about the relation between
physical claims and phenomenally conceived claims about phenomenal concepts.
Like all Type-B
physicalists, I take the existence of (first-order) phenomenal concept to imply
that (first-order) phenomenal mind-brain identity claims are a posteriori. In response to the challenge that these
claims are unique among a posteriori necessities in not hinging on semantically
unstable concepts, I argued that such uniqueness is adequately explained by the
use-mention feature of phenomenal concepts:
this feature explains why we take it that phenomenal concepts will refer
to the same referent whatever the facts, even though phenomenal concepts are
arguably unlike other semantically stable concepts in not requiring transparent
knowledge of the essential nature of their referents. As to the feeling that, even after this has
been said, there remains something disturbingly unexplanatory about phenomenal
mind-brain identities, my view is that this feeling doesn’t stem from any
semantic or epistemic peculiarity of these identities, but simply from the
prior ‘intuition of distinctness’ that militates against our believing these
identities to start with. (To the extent
we embrace this intuition, then of course we will feel a real ‘explanatory
gap’, for we will then want some causal explanation of why the physical brain
should ‘give rise to’ the supposedly separate phenomenal mind.)[23] As to the source of the intuition of
distinctness, I explained this by once more appealing to the use-mention
feature of phenomenal concepts, and the way it makes us think that
non-phenomenal modes of thought ‘leave out’ the phenomenal feelings.
Now I don’t see
why I can’t simply say all these things again, if Chalmers challenges me to
account for the extra gap between P and C which arises when we are thinking of
(first-order) phenomenal concept in (second-order) phenomenal terms, as on this
first horn of his dilemma. (Second-order)
phenomenal claims identifying the possession of (first-order) phenomenal
concepts with physical states will be a posteriori necessities. If these are held to be unusual among a
posteriori necessities in not involving semantic instability, I can point out
that the use-mention feature of (second-order) phenomenal concepts explains why
this should be so. If it is felt that,
even after this has been said, there seems to be something disturbingly unexplanatory
about claims identifying the possession of (first-order) phenomenal concept
with physical states, I attribute to a higher-level ‘intuition of
distinctness’, which arises because physical/functional ways of thinking about
(first-order) phenomenal concepts seems to ‘leave out’ the feelings which are
present when we think about (first-order) phenomenal concepts using
(second-order) phenomenal concepts.
In short, just as
the use-mention feature of (first-order) phenomenal concepts accounts for any
peculiarities of the conceptual gap between physical/functional claims and
(first-order) phenomenal claims about phenomenal properties, so does the
use-mention feature of (second-order) phenomenal concepts account for any
similar peculiarities in the gap between physical/functional claims P and
(second-order) phenomenal claims C about the possession of phenomenal concepts.
Of course,
Chalmers may now wish to ask about the relationship between physical/functional
claims P and (third-order) phenomenal claims C about the possession of
(second-order) phenomenal concepts. But
I am happy to go on as long as he is.
5.4
The Second Horn
Let me now turn to
the other horn of Chalmers’ dilemma.
Here P and not-C is not conceivable. We conceive of phenomenal concepts in
physical/functional terms, and so conceive of zombies as sharing our phenomenal
concepts, in virtue of conceiving them as sharing our physical/functional
properties.
Chalmers’ worry on
this horn is that phenomenal concepts so conceived will fail to explain our
epistemic relationship to consciousness.
For we don’t conceive of zombies as epistemically related to
consciousness as we are, even though on this horn we are conceiving them as
sharing our phenomenal concepts. So something
more than phenomenal concepts seems to be needed to explain our peculiar
epistemic relation to consciousness.
In order to rebut
this argument, and show that a physical/function conception of phenomenal
concepts allows a perfectly adequate account of our epistemic relation to
consciousness, I need to proceed in stages. Observe first that none of the points I have made
about our relationship to consciousness in this paper demands anything more
than a purely physical/functional conception of phenomenal concepts. To confirm this, we can check that all these
points would apply equally to zombies, conceived of as having
physical/functional phenomenal concepts, but no inner phenomenology. Note first that the zombies’ ‘phenomenal’ concepts
(the scare quotes are to signal that we are not now conceiving of these
concepts as involving any phenomenology) will be just as experience-dependent
as our own. Zombie Mary will need to
come out of her room to acquire a ‘phenomenal’ concept of red experience, and
when she does she will acquire some new non-indexical knowledge: she will come to know that seeing red =THAT experience (where this
is to be understood as using a material concept on the left-hand side and her
new experience-dependent ‘phenomenal’ concept on the right-hand side). Moreover, this kind of knowledge is arguably
unusual, in that it lays claim to an a posteriori necessity, yet it doesn’t
display the semantic instability characteristic of such claims. Still, zombie Type-B physicalists can invoke
the use-mention feature of zombie Mary’s new ‘phenomenal’ concept to
explain why that concept should come out as semantically stable even though its
possessors can be ignorant of the essential nature of its referent. Not that the zombie Type-B physicalists are
likely to have things all their own way, for they will also have to contend
with the zombie ‘intuition of distictness’—zombies who reflect on the nature of
their ‘phenomenal’ brain-mind claims might well note (using second-order
‘phenomenal’ concepts) that the left-hand sides ‘leave out’ a mental property
that is used on the right-hand sides, and conclude on this basis that
non-‘phenomenal’ concepts don’t mention the same mental properties as are
mentioned by ‘phenomenal’ concepts.
Still, zombie Type-B physicalists can point out that this is a
confusion, engendered by the peculiar use-mention feature of zombie
‘phenomenal’ concepts.
All in all, then,
everything I have said about our own epistemic relation to our conscious states
will be mirrored by the zombies’ relation to their corresponding states. I take this symmetry with zombies to show
that our own relationship to consciousness can be perfectly adequately
explained using a physical/functional conception of phenomenal properties. But Chalmers urges that the comparison cuts
the other way. Maybe, he allows, we can
suppose that zombies have states to which they stand in the same sort of
epistemic relation that we have to consciousness. But we mustn’t forget, he insists, that we
are also conceiving zombies as beings who lack our inner life, who have
no phenomenology. Given this, Chalmers
argues that an explanation of mental life that works for zombies can’t possibly
explain our relation to our own conscious phenomenology.
At this point it
will help to recall the basic Type-B physicalist attitude to zombies. Since Type-B physicalists hold that human
consciousness is in fact physical, they hold that zombies are metaphysically
impossible; any being who shares our
physical properties will therewith share our conscious properties; not even God could make a zombie. At the same time, Type-B physicalists
recognize that we have two way of thinking about phenomenal properties. This is why zombies are conceivable even
though impossible. We can apply one way
of thinking about phenomenal matters, but withhold the other—that is, we can
think of zombies as sharing our physical/functional properties, but as lacking
our phenomenal properties phenomenally conceived.
Given this, there
is no obvious reason why Type-B physicalists should be worried that a
physical/functional explanation of our epistemic relationship to consciousness
will apply equally to zombies. Physical/functional
duplicates of us will necessarily be conscious, just like us. True, our ability to think in phenomenal
terms makes it possible for us also to conceive of these duplicates as lacking
phenomenal properties, and so not related to consciousness as we are. But the fact that we can so conceive of zombies
needn’t worry the physicalist, who after all thinks that we are here conceiving
an impossibility which misrepresents our actual relationship to consciousness. We can imagine beings who are
physically/functionally just like us but who lack our inner life—but that
doesn’t mean that the physical/functional story is leaving something out, given
that in reality our inner life isn’t anything over and above the physical/functional
facts.
Let me conclude by
turning to ‘silicon zombies’. Here
things come out rather differently, since Type-B physicalism leaves it open
that silicon zombies are metaphysically as well as conceptually possible. Silicon zombies are possible beings who share
our functional properties, if necessary down to a fine level of detail, but who
are made of silicon-based materials rather than our carbon-based ones, and on
that account lack our conscious properties.
As it happens, I am inclined to the view that conscious properties are
identical with functional properties rather than strictly physical properties,
and that silicon zombies are therefore metaphysically impossible, even though
conceivable, just like full-on zombies.
However, nothing in Type-B physicalism as I have presented it (nor
indeed anything I have written about consciousness) requires this
identification of conscious properties with functional rather than physical ones,
so I am prepared to concede for the sake of the argument that silicon zombies
would lack conscious properties.
Now suppose
further that the ‘physical/functional’ conception of phenomenal concepts which
defines the second horn of Chalmers’ dilemma is in fact a functional
conception. (This seems reasonable—all
the non-phenomenal claims I have made about phenomenal concepts have hinged on
their functional workings, not their physical nature.) Since silicon zombies are our functional
duplicates, they will therefore have ‘phenomenal’ concepts, functionally
conceived, and these will mimic the operations of our own phenomenal
concepts: silicon Mary will need to come
out of her room to acquire a ‘phenomenal’ concept of red ‘experience’, silicon
subjects will suffer a ‘dualist intuition of distinctness’, and so on.
So my putative
explanation of our own epistemic relationship to consciousness is mirrored by
the matching relationship of the silicon zombies to its corresponding states,
even though the silicon zombies are missing the crucial thing that we
have—consciousness. And now, since we
are dealing with silicon zombies rather than full-on physical duplicates, I
can’t say that this asymmetry is an illusion generated by our conceiving an
impossibility, since by hypothesis the silicon zombies really wouldn’t have the
conscious properties that we humans possess.
Unlike full-on duplicates, silicon zombies really do lack something that
we have.
At this point, I
think that Type-B physicalists should bit the bullet and say that the thing
that differentiates us from the silicon zombies doesn’t make any difference to
the explanatory significance of phenomenal concepts. We might be related to something different,
but this doesn’t mean that we enjoy some special mode of epistemological
access our states which is not shared by the silicon zombies. After all, the silicon zombies’ ‘phenomenal’
concepts do successfully refer a certain range of silicon mental
properties—‘schmoncious’ properties—and Type-B physicalists can say that the silicon
zombies’ ‘phenomenal’ concepts relate them to these schmonscious properties in
just the way that our own phenomenal concepts relate us to our conscious
properties. True, these schmonscious
properties are not conscious ones, since by hypothesis we are supposing that
consciousness requires carbon-based physical make-up. But this does not mean that there is any
substantial explanatory asymmetry between the way our phenomenal concepts
relate us to our conscious states and the way the zombies’ ‘phenomenal’
concepts relate them to their schmonscious states. (After all, note that silicon zombie philosophers
can point out that we lack something that they have, given that
we lack the silicon-based make-up required for schomsciousness.)
Of course, if you are
a dualist, like David Chalmers, or indeed like anybody who is still in the grip
of the intuition of distinctness, then you will hold that there is some very
special extra property generated by carbon-based brains, and nothing
corresponding in the silicon zombies.
And you will think our introspective awareness relates us to this
special extra property, and so must involve some special capacity that we do
not share with the silicon zombies. But
physicalists reject any such special properties, extra to physical/functional
ones, and so have no reason to think that our relation to our conscious
properties is any different in kind from the silicon zombies’ relation to their
schmonscious properties. Phenomenal
concepts, functionally conceived, provide a perfectly good explanation of both
relationships.[24]
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[1] This worry has long been
pressed on me by my
[2] I will take no stand
on whether or not such ‘mixed demonstratives’ are equivalent to definite
descriptions.
[3] Cf.
Prinz 2002 especially chs 6 and 7.
[4] Here I am very much indebted
to Ruth Millikan’s On Clear and Confused Ideas (2000).
[5] It
should be noted that my assumption that phenomenology goes with categorization,
rather than with basic physical object representation, is denied by Jackendorf
1987 and Prinz 2000. However, I find
their arguments uncompelling.
[6] It is consistent with this that there should be
phenomenological differences when different patterns are involved within
or across subjects when they identify an individual bird (Jemima), or its type (mallard),
or indeed both (Jemima and a mallard).
[7] Couldn’t you have a standing
thought ‘that bird is a female’, say, even when you aren’t actively rehearsing
the thought—and won’t this imply a sense in which you can think about the bird
even when not perceiving or imagining it?
Maybe so. But I am interested
here in the involvement of concepts in occurrent thoughts, not in standing
ones.
[8] Let me be more specific about the possibility at issue here. The idea is not that you might refer
non-perceptually using familiar indexical constructions, as in ‘the bird I saw
in my garden yesterday morning’. Rather,
the non-perceptual reference is supposed to derive more immediately from the prior
perceptual contact, in such a way as to remain possible even if you have
forgotten where and when you previously perceived the bird.
[9] Those who think in terms of ‘recognitional
concepts’ may be inclined to argue that perceptually derived concepts, along
with the perceptual concepts they derive from, require an ability to recognize
referents perceptually. Against this, I
have already argued that even ordinary perceptual concepts do not require their
possessors to be any good at recognizing referents. With perceptually derived concepts I would
say that recognitional powers can atrophy still further, even to the extent
where there is no disposition perceptually to identify anything as the
referent of your concept. Suppose that
you previously referred to something perceptually. But your stored sensory template has faded,
and you can no longer perceptually reidentify new instances when you come
across them, and perhaps you can’t even perceptually imagine them. It doesn’t seem to me that this need stop you
being able to rehearse your belief ‘That bird was female’, say, where
the underlined phrase still refers to the original referent. Anaphora is perhaps a useful model
here. Consider someone who first thinks
about some entity perceptually, and then keeps coming back to it in thought,
even after the ability to reidentify the entity has faded. It seems natural to suppose that these
thoughts will continue to refer to the same entity, even in the absence of
continued recognitional abilities.
[10] I would like to thank
Dorothy Edgington for drawing my attention to this issue.
[11] This leaves it open, of
course, that there may be other good arguments against epiphenomenalism, apart
from a priori arguments. Cf. Papineau
2002 section 1.4.
[12] Does this mean that perceptual experiences are the
only items that can be thought about phenomenally? This seems doubtful.
To consider just a couple of further cases, what about emotions, and
pains? At first pass, it certainly seems
that these states too can be picked out by phenomenal concepts—yet they are not
obviously examples of perceptual experiences.
There are two ways to go here.
One would be to understand perception in a broad enough way to include
such states. After all, emotions and
pains are arguably representational states, and so could on these grounds be
held to be a species of perception.
Alternatively, we might distinguish these states from perceptions, but
nevertheless allow that they are similar enough for us to think about them in
ways that parallels phenomenal thinking about obviously perceptual states. I have no strong views on this choice, but in
what follows I shall simplify the exposition by sticking to perceptions.
[13] It might occur to some readers that
another answer to the challenge would be to insist that Mary must really be
using some old pre-exposure material concept of red experience when she thinks
the supposedly problematic thought.
However, this will not serve. To
see clearly why, it will help to vary the Mary thought-experiment
slightly. Suppose that, on her exposure,
Mary was shown a coloured piece of paper, rather than a rose, and that she
wasn’t told what colour it was. The
objection would seem still to stand. The
conceptual powers she acquires from her exposure would still seem to enable her
later truly to think, I am not now having
or imagining THAT experience. But
now she can’t be using any of her old pre-exposure concepts to refer to
the experience. For, if she doesn’t know
what colour the paper was, she won’t know which of her old concepts to use.
[14] For versions of this
argument see Chalmers 1996, Jackson 1998, Bealer 2002. The notion of semantic stability is due to
Bealer. I would like to thank Philip
Goff for helping me to understand these issues.
[15]
Thus we might this of semantic instability are requiring, not the
descriptive fixing of reference, but only that thinkers who possesses the
relevant concepts will pick out different entities as their referents given
different scenarios presented in fundamental terms (Chalmers and Jackson 2001,
Chalmers 2002). (Since physicalists will
equate fundamental terms with physical terms, this characterization of semantic
instability then leads to the thesis that physicalism implies that all the
facts must follows a priori from the physical facts.) I myself am very dubious that proper name and
perceptual concepts are unstable in this sense—this seems to follow only if we
illegitimately presuppose that thinkers need a potential appreciation of the
semantic workings of their proper name and perceptual concepts in order to
possess them. Another possible
understanding of semantic instability is as requiring only that the facts which
relate concepts to their referents might have been different. (Thus Chalmers 1996, p. 373 ‘if the subject
cannot know that R is P a priori, then reference to R and P is fixed in
different ways and the reference-fixing intensions can come apart in certain
conceivable situations.’) Note that this
latter understanding will not require physicalists to hold that all the facts
must follows a priori from the physical facts, given that it does not seem an a
priori matter which facts relate concepts to their referents. I have an open mind on whether this last
understanding of semantic stability leaves phenomenal concepts stable while
implying that proper name and perceptual concepts are not. Cf. the next footnote.
[16] Does this line of thought
really distinguish proper name and perceptual concepts from phenomenal
concepts? There are worries on both
sides. First, it is not clear how we are
to conceive of Cicero and red as referring to different things
while remaining the same concept—note in particular that it is by no
means enough that the words ‘Cicero’ or ‘red’ might have referred to
different things. Second, it is not obvious
exactly how to individuate phenomenal concepts like pain so as to make it impossible for them to refer to different
things—the issues discussed in subsection 3.4 are relevant here.
[17] Thus consider Chalmers 2003b p. 233: ‘Something very unusual is going on here. . .
. In the pure phenomenal case . . . the
quality of the experiences plays a role in constituting the epistemic content
of the concept . . . One might say very
loosely that in this case, the referent of the concept is somehow present inside
the concept’s sense, in a way much stronger than in the usual cases of “direct
reference”.’
[18] It is consistent with this
diagnosis that thought-experiments about possible zombies might nevertheless
play an epistemologically significant role in clarifying the content of
our intuitions. (I owe this point to
George Bealer.) Suppose it is agreed on
all sides that pains and nociceptive-specific neuronal activity are perfectly
correlated in the actual world. We might
then wonder whether this is a matter of property identity or whether it is a
correlation between two distinct properties.
One way of resolving this would be to ask whether ‘these’ properties could
come apart—for example, are zombies possible?
In this way, the intuitive possibility of zombies could serve to make it
clear to us that, even though we take pain and nociceptive-specific neuronal
activity to be perfectly correlated in the actual world, we still view them as
distinct properties. However, viewing
the intuition that zombies are possible as having this epistemological
significance is quite different from saying that pain = nociceptive-specific
neuronal activity seems contingent.
The story I have just told has no place for the thought that pain is
identical to nociceptive-specific neuronal activity in the actual world but
distinct in some other possible world.
On the contrary, the epistemological significance just ascribed to the
zombie thought-experiment hinges on the fact that actual identity stand or
falls with necessary identity. I owe
this point to George Bealer.
[19] Physicalists are often too ready to see things in Kripkean terms,
and to seek some reading of mind-brain claims on which true mind-brain
identities might have been false. Thus
Perry (2001) assimilates phenomenal concepts to indexicals, and then says that
the possibility that ‘pain’/‘this brain state’ might have picked out some
different state than C-fibres firing ‘underlies the sense of contingency’. I don’t recognize the intuition that this
story is supposed to explain. When I
think that ‘pains might not have been C-fibres firing’, my thought isn’t that ‘this
cognitive process (whatever it is) might (have turned out) not (to) be
C-fibres firing’, but simply that ‘pains aren’t C-fibres firing’.
[20] See Papineau 1993b. For an alternative explanation of the
intuition of distinctness, see Melnyk 2003.
[21] Note how my
explanation implies that the intuition of distinctness will only arise when we
are thinking with phenomenal concepts, which use the very states they mention,
and not when we are thinking with phenomenally derived concepts. This seems to me quite in accord with the
facts.
[22] This ‘first-order’ and ‘second-order’ talk
should not be taken to imply some hierarchy of differently structured
concepts. When I say that we can think
about a ‘first-order’ phenomenal concept using ‘second-order’ one, all I mean
is that the phenomenal property used by the ‘first-order’ phenomenal concept
can itself be thought about using a phenomenal concept. There is no reason why the latter phenomenal
concept should be differently structured from any other—indeed it can be the
same (first-order) phenomenal concept that uses the phenomenal property in
question. Still, the terminology of
‘first-’ and ‘second-order’ will help clarify my line of argument.
[23] For my reasons for thinking
that there is nothing semantically or epistemically peculiar about mind-brain
identities, and that the impression of a distinctive ‘explanatory gap’ derives
solely from the associated intuition of distinctness, see Papineau 2002 ch 5.
[24] Earlier versions of this paper were read at the