RATIO, Vol. XVII no 1 (March 04)
LOAR’S DEFENCE OF PHYSICALISM
Stephen Law
Abstract
Brian Loar
believes he has refuted all those antiphysicalist arguments that take as their
point of departure observations about what is or isn’t conceivable. I argue
that there remains an important, popular and plausible-looking form of
conceivability argument that Loar has entirely overlooked. Though he may not
have realized it, Saul Kripke presents, or comes close to presenting, two
fundamentally different forms of conceivability argument. I distinguish the two
arguments and point out that while Loar has succeeded in refuting one of
Kripke’s arguments he has not refuted the other. Loar is mistaken: physicalism
still faces an apparently insurmountable conceptual obstacle.
1. Antiphysicalist arguments and
intuitions
In
his paper Phenomenal States, Brian Loar makes the following claim:
Antiphysicalist arguments and intuitions take
off from a sound intuition about concepts. Phenomenal concepts are conceptually
irreducible in this sense: they neither imply, nor are implied by,
physical-functional concepts. . . The antiphysicalist takes this a good deal
further, to the conclusion that phenomenal qualities are themselves irreducible,
are not physical-functional properties.[i]
According to Loar, it is in taking this second step that the
antiphysicalist goes wrong: ‘We have to distinguish between concepts and
properties’.[ii]
The independence of our concepts of, say, pain and C-fibre firing – the fact
that there is nothing conceptually problematic about the suggestion that pain
might exist without C-fibre firing and vice verse – does not entail that these
two concepts do not pick out one and the same property.
Of course, the independence of a pair concepts is
not usually taken to entail that the corresponding properties are
non-identical. After all, the independent concepts heat and molecular
motion pick out the same property, as do alcohol and CH3CH2OH.
Yet antiphysicalists believe the independence of the concepts pain and C-fibre
firing entails that pain cannot be identical to C-fibre firing. Why so?
According to Loar, because the concepts pain and C-fibre firing pick out
the properties they do by way of essential features of those properties.
On Loar’s understanding, at least implicit in the anti-physicalist’s reasoning
here is the kind of argument that is explicitly set out in Kripke’s Naming
and Necessity. That argument runs as follows.
2. The Kripkean argument
The concepts heat and molecular motion
pick out the same property, yet they are independent concepts. What explains
this independence, and thus the fact that heat = molecular motion is not an a
priori truth, is the fact that the concept heat picks out the property
in question by way of what Loar calls a contingent mode of presentation.
That is to say, heat picks out the property it does by way of a merely
contingent feature of that property. We think of heat as that property that feels
like this, and of course it is contingent that heat feels to us the way it
does: it might have felt differently. It is because we can’t know a priori the
contingent fact that molecular motion feels like this that we can’t know
a priori that molecular motion is what heat essentially is.
In the case of pain = C-fibre
firing, on the other hand, each of the concepts involved picks out the property
it does by way of a non-contingent mode of presentation. In particular,
while we think of pain as the property that feels like this, feeling
like this is an essential property of pain. But then we cannot similarly
explain why, if pain = C-fibre firing, this isn’t a priori. Kripke concludes
that pain is not identical with C-fibre firing. If these properties were
identical, the identity would be knowable a priori. It isn’t.
3. The implicit assumption
Loar points out,
correctly, that Kripke’s argument, as expounded by Loar, relies on the
following implicit assumption:
The only
way to account for the a posteriori status of a true property identity is this:
one of the terms expresses a contingent mode of presentation.[iii]
Call this principle (P). It is this principle that Loar attacks. Loar
agrees that one way in which one might explain the a posteriori character of a
property identity would be to point out that one or both concepts involve a
contingent mode of presentation; however, Loar denies that this is the only
possible explanation. Thus, while Loar agrees with Kripke that the concepts pain
and C-fibre firing both pick out the properties they do via non-contingent
modes of presentation, he denies that this, in combination with the fact that
pain = C-fibre firing is not a priori, entails that pain is not identical with
C-fibre firing. Loar explains as follows.
[A] phenomenal concept rigidly designates the property it picks out.
But then it rigidly designates the same property that some theoretical physical
concept rigidly designates. This could seem problematic, for if a concept
rigidly designates a property not via a contingent mode of presentation, must that
concept not capture the essence of the designated property? And if two concepts
capture the essence of the same property, must we not be able to know this a
priori? These are equivocating uses of ‘capture the essence of’. On one use, it
expresses a referential notion that comes to no more than ‘directly rigidly
designate’. On the other, it means something like ‘be conceptually
interderivable with some theoretical predicate that reveals the internal
structure of’ the designated property. But the first does not imply the second.
What is correct in the observation about rigid designation has no tendency to
imply that the two concepts must be a priori interderivable.[iv]
Loar has sketched out in more
detail how concepts that ‘capture the essence of’ the same property may
nevertheless fail to be conceptually convertible; he suggests[v]
that phenomenal concepts like pain and
theoretical physical concepts like C-fibre firing are realized in very
different parts of the brain. Phenomenal concepts get their distinctiveness
from their close connections with the experiential parts of the brain.
Theoretical concepts like that of C-fibre firing, on the other hand, have their
origins in other, quite different concept-forming faculties. Thus the two
concepts are unlikely to be conceptually convertible anyway, even if
they do pick out the same property. So it is plausibly just a psychological
fact about us that the concepts pain and C-fibre firing are not
conceptually convertible. Pace Kripke, no deep metaphysical conclusions
about the nature of pain can legitimately be drawn from the existence of this
psychological fact. So there is, after all, no conceptual obstacle to our
accepting physicalism.
4. A counterexample to
Principle (P)
Loar is surely right to deny (P).
Indeed, it is not difficult to think of counter-examples (though Loar does not
himself provide any).
Take, for example, the property of
being a tiger. On certain fairly plausible assumptions about the essentiality
of both some unique genetic feature and some unique piece of evolutionary
history to the species tiger, one may conceive of the property of being
a tiger as:
Property A: the property of belonging to the animal species with genetic feature
G
(where G is a genetic feature unique and essential to the tiger), or
as:
Property B: the property of belonging
to the animal species with evolutionary history E
(where E is a piece of evolutionary history unique and essential to the
tiger). These conceptions pick out the very same property. They do so by way of
essential features. Yet these two conceptions are not a priori interderivable.
It would take an empirical investigation to establish that Property A =
Property B. As principle (P) denies this, (P) is false.
The key point to recognise here is
that while a conception may pick out a property via an essential feature, it
need not be that property’s only essential feature; nor need all that
property’s essential features be conceptually interderivable.
5. The no-fool’s-pain
argument
I accept both that Kripke’s argument
as presented by Loar rests on (P) and that (P) is mistaken. However, a quite
different argument is also suggested by what Kripke has to say about
physicalism. As I explain below, while this alternative argument also turns on
considerations about conceivability, it does not depend upon principle
(P). Indeed, the argument is immune to Loar’s criticism. I call this
alternative argument the no-fool’s-pain argument.
First, note there is no conceptual obstacle to supposing that, though
it seems to one that one is clearly in pain, ones C-fibres are not firing.
Whether or not this is a genuine metaphysical possibility, it is at least not
ruled out a priori.
Now consider the identity theory that pain is
necessarily identical with (say) C-fibre firing. This theory entails that
necessarily: if someone’s C-fibres are not firing, then they are not in pain.
But then the identity theory plus the
conceptual coherence claim together commit the identity theorist to the
conceptual possibility of fool’s pain. If there is no conceptual
obstacle to supposing that, though it seems to one that one is in pain, ones
C-fibres are not firing, then, if one supposes that pain is identical with
C-fibre firing, there is no conceptual obstacle to supposing that, though it
seems to one that one is in pain, one isn’t really in pain (i.e. because ones
C-fibres are not firing). To accept the identity theory is, in effect, to allow
that fool’s pain should at least be a conceptual possibility. But fool’s pain
is not a conceptual possibility. The
concept of pain itself demands that if it seems to one that one is in pain,
then one is. It follows that the identity theory is false.
6. No-fool’s-X arguments
This is, of course, a
familiar form of argument. It runs as follows:
(i)
Something
that appears to be X but not Y is at least a conceptual possibility
(ii)
If X is identical with Y, then Y is
a necessary condition of X
(iii)
Therefore,
if X is identical with Y, in conceiving of something that appears to be X but
isn’t Y one is conceiving of fool’s X (i.e. something that appears
to be X but isn’t because a condition necessary for X is unfulfilled)
(iv)
But
fool’s X is not a conceptual possibility
(v)
Therefore
X is not identical with Y
In fact one
finds arguments of this form used against a whole raft of identity claims.
Take, for example, the claim that colour properties are identical with
certain microstructural properties (such as the property of reflecting light of
such-and-such a wavelength). In this case, too, it seems that our conception of
one of the two properties alleged to be identical won’t allow for the
conceptual possibility of the kind of gap between appearance and reality
required if the property identity is to hold.
To explain: ‘fool’s gold’ – stuff that has the appearance of gold but
isn’t – is a conceptual possibility. Our concept of gold allows for the
possibility of gold having a ‘real essence’: a deep microstructural property
possession of which is necessary if something is to qualify as a sample of
gold. We can envisage gold-like stuff that, because it lacks whatever is the
essential microstructural property in question, isn’t really gold. Because
‘fool’s gold’ is a conceptual possibility, so it is conceptually possible for
it to turn out that the property of being gold and the property of having such-and-such
a deep microstructural constitution are identical.
By contrast, it seems we can know a priori that colours do not possess
such microstructural ‘real essences’. We can know this precisely because
‘fool’s red’ is a conceptual impossibility. It is a conceptual truth that
(roughly) if something typically looks red under standard conditions, then it is red. But this entails that the
property of being red cannot turn out to be identical with some microstructural
property. If such an identity did hold, then, because possession of that
property would be a necessary condition of something’s being red, and because
we can conceive of something typically looking red without that property, so
fool’s red would be a conceptual
possibility.[vi]
The no-fool’s-pain argument is analogous to the above. It is a
conceptual truth that if it seems to one that one is in pain, then one is in
pain. The concept of pain doesn’t allow for appearance and reality to come
apart in that way. But this, in conjunction with the claim that the identity of
pain with some physical or physical-functional property would be necessary,
entails that pain cannot turn out to be identical with any such property – in
particular, it entails that pain cannot turn out to have a microstructural
‘real essence’ in the way that gold does. (Notice, by-the-way, that other
identity claims are similarly blocked by the observation that ‘fool’s sweet’
and ‘fool’s jaundice’ are conceptual impossibilities.)
Loar has done nothing to discredit this popular form of argument as
applied either to the theory that red is identical with a wavelength of light
or to the theory that pain is identical with some physical or
physical-functional feature of the nervous system. For in neither case does
the argument rely on principle (P).
7. Is the no-fool’s-pain argument Kripke’s?
Kripke does offer the argument that Loar attributes to him. However,
the three premises required to run the no-fool’s-pain argument – (i) if pain is
C-fibre firing then C-fibre firing is a necessary condition of pain, (ii) pain
without C-fibre firing is a conceptual possibility, and (iii) fool’s pain is a
conceptual impossibility – are also all supplied by Kripke. Although the
no-fool’s-pain argument is never explicitly formulated, the premises and conclusion
are all there in Naming and Necessity.
Indeed, if the argument that Loar attributes to Kripke is all
that Kripke has to offer, one wonders why Kripke goes to the bother of
mentioning that there is, as he puts it, no such thing as a ‘qualitatively
identical counterpart’ to pain that isn’t pain, i.e. no such thing as fool’s
pain. For the fact that fool’s pain is a conceptual impossibility is actually
irrelevant to the argument Loar refutes. All that argument requires is that
pain be picked out via a non-contingent mode of presentation: namely, that it feels
like this. It is not required that this feature be sufficient
for pain. Yet the observation that ‘the notion of an epistemic situation qualitatively identical to one in
which the observer had a sensation S simply is one in which the
observer had that sensation’ is clearly considered by Kripke to be one of his
key premises.[vii]
It seems not unreasonable, then, to suppose that the argument Loar
refutes is not the only argument Kripke has to offer, and that the
no-fool’s-pain argument may also be one that Kripke has in mind.
Conclusion
According to Loar, all antiphysicalist
arguments and intuitions take as their starting point the (correct) observation
that phenomenal concepts like pain and physical-functional concepts such as
C-fibre firing are not interderivable. These arguments and intutions all
ultimately rest upon principle (P). Loar points out, correctly, that, while (P)
may have a certain superficial appeal (thus explaining our antiphysicalist
intuitions), it is in fact false. Thus there is, according to Loar, no
conceptual obstacle to our accepting physicalism.
However, as should now be clear, there exists
another, powerful antiphysicalist argument that has an entirely different
starting point. The argument appeals to a quite different observation: that our
concept of pain exhaustively captures the essence of that property (i.e.
that nothing more is required for pain than that it feel like this).
Thus it is conceptually ruled out that pain might turn out to have a hidden,
physical-functional ‘real essence’. Loar has not dealt with this
antiphysicalist argument.
Crucially, the alternative argument does not rely on principle (P).
What
Loar tries to explain is why, if pain is identical with C-fibre firing, the
suggestion that pain might not be C-fibre firing isn’t conceptually
incoherent. What Loar goes no way towards explaining is why, if pain is C-fibre
firing, fool’s pain is conceptually incoherent. Pace Loar, there
remains a very considerable conceptual obstacle to our accepting physicalism,
an obstacle that Loar has not explained away.
Kripke
does offer the argument Loar attributes to him. However, the resources required
to construct the no-fool’s-pain argument are also supplied by Kripke. Perhaps
Kripke does not himself realize that his writings present, or come close to
presenting, (at least) two fundamentally different antiphysicalist arguments.
By showing that principle (P) is false, Loar has refuted one of these
arguments. He has not refuted the other.
Heythrop College, University of
London,
Kensington Square,
London
W8 5HQ
think@royalinstitutephilosophy.org
[i] Brian Loar, ‘Phenomenal States’ in The Nature
of Consciousness, (eds.) Ned Block, Owen Flanagan and Guven Guzeldere (London:
MIT Press, 1997), p. 597.
[ii]
Loar, ‘Phenomenal States’, p. 597.
[iii]
Loar, ‘Phenomenal States’, p. 600.
[iv]
Loar, ‘Phenomenal States’, p. 603.
[v]
Lecture to the Sensation and
Consciousness conference of the University of London School of
Advanced Study Philosophy Programme at Senate House, University of London,
Friday 3rd December, 1999.
[vi]
Colin McGinn presents this argument in Colin McGinn, The Subjective View (Oxford: The Clarendon Press, 1983), pp.11-12.
[vii]
Saul Kripke, Naming and Necessity
(Oxford: Blackwell,1980), p.152.
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