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What is it like to be a
bat? (The
Philosophical Review LXXXIII, 4, October 1974: 435-50.) Consciousness
is what makes the mind-body problem really intractable. Perhaps that is why current
discussions of the problem give it little attention or get it obviously
wrong. The recent wave of reductionist euphoria has produced several analyses
of mental phenomena and mental concepts designed to explain the possibility
of some variety of materialism, psychophysical identification, or reduction.1
But the problems dealt with are those common to this type of reduction and
other types, and what makes the mind-body problem unique, and unlike the
water-H2O problem or the Turing machine-IBM machine problem or the
lightning-electrical discharge problem or the gene-DNA problem or the oak
tree-hydrocarbon problem, is ignored. Every
reductionist has his favorite analogy from modern science. It is most
unlikely that any of these unrelated examples of successful reduction will
shed light on the relation of mind to brain. But philosophers share the
general human weakness for explanations of what is incomprehensible in terms
suited for what is familiar and well understood, though entirely different.
This has led to the acceptance of implausible accounts of the mental largely
because they would permit familiar kinds of reduction. I shall try to explain
why the usual examples do not help us to understand the relation between mind
and body—why, indeed, we have at present no conception of what an explanation
of the physical nature of a mental phenomenon would be. Without consciousness
the mind-body problem would be much less interesting. With consciousness it
seems hopeless. The most important and characteristic feature of conscious
mental phenomena is very poorly understood. Most reductionist theories do not
even try to explain it. And careful examination will show that no currently
available concept of reduction is applicable to it. Perhaps a new theoretical
form can be devised for the purpose, but such a solution, if it exists, lies
in the distant intellectual future.
We
may call this the subjective character of experience. It is not captured by
any of the familiar, recently devised reductive
analyses of the mental, for all of them are logically compatible with its
absence. It is not analyzable in terms of any explanatory system of
functional states, or intentional states, since these could be ascribed to
robots or automata that behaved like people though they experienced nothing.2
It is not analyzable in terms of the causal role of experiences in relation
to typical human behavior—for similar reasons.3 I do not deny that
conscious mental states and events cause behavior, nor that they may be given
functional characterizations. I deny only that this kind of thing exhausts
their analysis. Any reductionist program has to be based on an analysis of
what is to be reduced. If the analysis leaves something out, the problem will
be falsely posed. It is useless to base the defense of materialism on any
analysis of mental phenomena that fails to deal explicitly with their
subjective character. For there is no reason to suppose that a reduction
which seems plausible when no attempt is made to account for consciousness
can be extended to include consciousness. With out some idea, therefore, of
what the subjective character of experience is, we cannot know what is
required of physicalist theory. While
an account of the physical basis of mind must explain many things, this
appears to be the most difficult. It is impossible to exclude the
phenomenological features of experience from a reduction in the same way that
one excludes the phenomenal features of an ordinary substance from a physical
or chemical reduction of it—namely, by explaining them as effects on the
minds of human observers.4 If physicalism is to be defended, the
phenomenological features must themselves be given a physical account. But
when we examine their subjective character it seems that such a result is
impossible. The reason is that every subjective phenomenon is essentially
connected with a single point of view, and it seems inevitable that an
objective, physical theory will abandon that point of view. Let
me first try to state the issue somewhat more fully than by referring to the
relation between the subjective and the objective, or between the pour-soi and the en-soi.
This is far from easy. Facts about what it is like to be an X are very
peculiar, so peculiar that some may be inclined to doubt their reality, or
the significance of claims about them. To illustrate the connection between
subjectivity and a point of view, and to make evident the importance of
subjective features, it will help to explore the matter in relation to an
example that brings out clearly the divergence between the two types of conception,
subjective and objective. I
assume we all believe that bats have experience. After all, they are mammals,
and there is no more doubt that they have experience than that
mice or pigeons or whales have experience. I have chosen bats instead
of wasps or flounders because if one travels too far down the phylogenetic tree, people gradually shed their faith that
there is experience there at all. Bats, although more closely related to us
than those other species, nevertheless present a range of activity and a
sensory apparatus so different from ours that the problem I want to pose is
exceptionally vivid (though it certainly could be raised with other species).
Even without the benefit of philosophical reflection, anyone who has spent
some time in an enclosed space with an excited bat knows what it is to
encounter a fundamentally alien form of life. I
have said that the essence of the belief that bats have experience is that
there is something that it is like to be a bat. Now we know that most bats
(the microchiroptera, to be precise) perceive the
external world primarily by sonar, or echolocation, detecting the
reflections, from objects within range, of their own rapid, subtly modulated,
high-frequency shrieks. Their brains are designed to correlate the outgoing
impulses with the subsequent echoes, and the information thus acquired
enables bats to make precise discriminations of distance, size, shape,
motion, and texture comparable to those we make by vision. But bat sonar,
though clearly a form of perception, is not similar in its operation to any
sense that we possess, and there is no reason to suppose that it is
subjectively like anything we can experience or imagine. This appears to
create difficulties for the notion of what it is like to be a bat. We must
consider whether any method will permit us to extrapolate to the inner life
of the bat from our own case,5 and if
not, what alternative methods there may be for understanding the notion. Our
own experience provides the basic material for our imagination, whose range
is therefore limited. It will not help to try to imagine that one has webbing
on one's arms, which enables one to fly around at dusk and dawn catching
insects in one's mouth; that one has very poor vision, and perceives the
surrounding world by a system of reflected high-frequency sound signals; and
that one spends the day hanging upside down by one's feet in an attic. In so
far as I can imagine this (which is not very far), it tells me only what it
would be like for me to behave as a bat behaves. But that is not the
question. I want to know what it is like for a bat to be a bat. Yet if
I try to imagine this, I am restricted to the resources of my own mind, and
those resources are inadequate to the task. I cannot perform it either by
imagining additions to my present experience, or by imagining segments
gradually subtracted from it, or by imagining some combination of additions,
subtractions, and modifications. To
the extent that I could look and behave like a wasp or a bat without changing
my fundamental structure, my experiences would not be anything like the
experiences of those animals. On the other hand, it is doubtful that any
meaning can be attached to the supposition that I should possess the internal
neurophysiological constitution of a bat. Even if I
could by gradual degrees be transformed into a bat, nothing in my present
constitution enables me to imagine what the experiences of such a future
stage of myself thus metamorphosed would be like.
The best evidence would come from the experiences of bats, if we only knew
what they were like. So
if extrapolation from our own case is involved in the idea of what it is like
to be a bat, the extrapolation must be incompletable.
We cannot form more than a schematic conception of what it is like.
For example, we may ascribe general types of experience on the basis
of the animal's structure and behavior. Thus we describe bat sonar as a form
of three-dimensional forward perception; we believe that bats feel some
versions of pain, fear, hunger, and lust, and that they have other, more
familiar types of perception besides sonar. But we believe that these
experiences also have in each case a specific subjective character, which it
is beyond our ability to conceive. And if there's conscious life elsewhere in
the universe, it is likely that some of it will not be describable even in
the most general experiential terms available to us.6 (The problem
is not confined to exotic cases, however, for it exists between one person
and another. The subjective character of the experience of a person deaf and
blind from birth is not accessible to me, for example, nor presumably is mine
to him. This does not prevent us each from believing that the other's
experience has such a subjective character.)
This
brings us to the edge of a topic that requires much more discussion than I
can give it here: namely, the relation between facts on the one hand and
conceptual schemes or systems of representation on the other. My realism
about the subjective domain in all its forms implies a belief in the
existence of facts beyond the reach of human concepts. Certainly it is
possible for a human being to believe that there are facts which humans never
will possess the requisite concepts to represent or comprehend.
Indeed, it would be foolish to doubt this, given the finiteness of humanity's
expectations. After all there would have been transfinite numbers even if
everyone had been wiped out by the Black Death before Cantor discovered them.
But one might also believe that there are facts which could not ever
be represented or comprehended by human beings, even if the species lasted
for ever—simply because our structure does not permit us to operate with
concepts of the requisite type. This impossibility might even be observed by
other beings, but it is not clear that the existence of such beings, or the
possibility of their existence, is a precondition of the significance of the
hypothesis that there are humanly inaccessible facts. (After all, the nature
of beings with access to humanly inaccessible facts is presumably itself a
humanly inaccessible fact.) Reflection on what it is like to be a bat seems to
lead us, therefore, to the conclusion that there are facts that do not
consist in the truth of propositions expressible in a human language. We can
be compelled to recognize the existence of such facts without being able to
state or comprehend them. I
shall not pursue this subject, however. Its bearing on the topic before us
(namely, the mind-body problem) is that it enables us to make a general
observation about the subjective character of experience. Whatever may be the
status of facts about what it is like to be a human being, or a bat, or a
Martian, these appear to be facts that embody a particular point of
view. I
am not adverting here to the alleged privacy of experience to its possessor.
The point of view in question is not one accessible only to a single
individual. Rather it is a type. It is often possible to take up a
point of view other than one's own, so the comprehension of such facts is not
limited to one's own case. There is a sense in which phenomenological facts
are perfectly objective: one person can know or say of another what the
quality of the other's experience is. They are subjective,
however, in the sense that even this objective ascription of experience is
possible only for someone sufficiently similar to the object of ascription to
be able to adopt his point of view—to understand the ascription in the first
person as well as in the third, so to speak. The more different from oneself
the other experiencer is,
the less success one can expect with this enterprise. In our own case we occupy
the relevant point of view, but we will have as much difficulty understanding
our own experience properly if we approach it from another point of view as
we would if we tried to understand the experience of another species without
taking up its point of view.8 This
bears directly on the mind-body problem. For if the facts of experience—facts
about what it is like for the experiencing organism—are accessible
only from one point of view, then it is a mystery how the true character of
experiences could be revealed in the physical operation of that organism. The
latter is a domain of objective facts par excellence—the kind that can
be observed and understood from many points of view and by individuals with
differing perceptual systems. There are no comparable imaginative obstacles
to the acquisition of knowledge about bat neurophysiology by human
scientists, and intelligent bats or Martians might learn more about the human
brain than we ever will. This
is not by itself an argument against reduction. A Martian scientist with no
understanding of visual perception could understand the rainbow, or
lightning, or clouds as physical phenomena, though he would never be able to
understand the human concepts of rainbow, lightning, or cloud, or the place
these things occupy in our phenomenal world. The objective nature of the
things picked out by these concepts could be apprehended by him because,
although the concepts themselves are connected with a particular point of
view and a particular visual phenomenology, the things apprehended from that
point of view are not: they are observable-from the point of view but
external to it; hence they can be comprehended from other points of view
also, either by the same organisms or by others. Lightning has an objective
character that is not exhausted by its visual appearance, and this can be
investigated by a Martian without vision. To be precise, it has a more
objective character than is revealed in its visual appearance. In speaking of
the move from subjective to objective characterization, I wish to remain
noncommittal about the existence of an end point, the completely objective
intrinsic nature of the thing, which one might or might not be able to reach.
It may be more accurate to think of objectivity as a direction in which the
understanding can travel. And in understanding a phenomenon like lightning,
it is legitimate to go as far away as one can from a strictly human
viewpoint.9 In
the case of experience, on the other hand, the connection with a particular
point of view seems much closer. It is difficult to understand what could be
meant by the objective character of an experience, apart from the
particular point of view from which its subject apprehends it. After all,
what would be left of what it was like to be a bat if one removed the
viewpoint of the bat? But if experience does not have, in addition to its
subjective character, an objective nature that can be apprehended from many
different points of view, then how can it be supposed that a Martian
investigating my brain might be observing physical processes which were my
mental processes (as he might observe physical processes which were bolts of
lightning), only from a different point of view? How, for that matter, could
a human physiologist observe them from another point of view?10 We
appear to be faced with a general difficulty about psychophysical reduction.
In other areas the process of reduction is a move in the direction of greater
objectivity, toward a more, accurate view of the real nature of things. This
is accomplished by reducing our dependence on individual or species-specific
points of view toward the object of investigation. We describe it not in
terms of the impressions it makes on our senses, but in terms of its more
general effects and of properties detectable by means other than the human
senses. The less it depends on a specifically human viewpoint, the more
objective is our description. It is possible to follow this path because
although the concepts and ideas we employ in thinking about the external
world are initially applied from a point of view that involves our perceptual
apparatus, they are used by us to refer to things beyond themselves—toward
which we have the phenomenal point of view. Therefore we can abandon
it in favor of another, and still be thinking about the same things. Experience
itself however, does not seem to fit the pattern.
The idea of moving from appearance to reality seems to make no sense here.
What is the analogue in this case to pursuing a more objective understanding
of the same phenomena by abandoning the initial subjective viewpoint toward
them in favour of another that is more objective
but concerns the same thing? Certainly it appears unlikely that we
will get closer to the real nature of human experience by leaving behind the
particularity of our human point of view and striving for a description in
terms accessible to beings that could not imagine what it was
like to be us. If the subjective character of experience is fully
comprehensible only from one point of view, then any shift to greater
objectivity—that is, less attachment to a specific viewpoint—does not take us
nearer to the real nature of the phenomenon: it takes us farther away from
it.
But
while we are right to leave this point of view aside in seeking a fuller
understanding of the external world, we cannot ignore it permanently, since
it is the essence of the internal world, and not merely a point of view on
it. Most of the neobehaviorism of recent
philosophical psychology results from the effort to substitute an objective
concept of mind for the real thing, in order to have nothing left over which
cannot be reduced. If we acknowledge that a physical theory of mind must
account for the subjective character of experience, we must admit that no
presently available conception gives us a clue how this could be done. The
problem is unique. If mental processes are indeed physical processes, then
there is something it is like, intrinsically,11
to undergo certain physical processes. What it is for such a thing to be the
case remains a mystery. What
moral should be drawn from these reflections, and what should be done next?
It would be a mistake to conclude that physicalism must be false. Nothing is
proved by the inadequacy of physicalist hypotheses that assume a faulty
objective analysis of mind. It would be truer to say that physicalism is a
position we cannot understand because we do not at present have any
conception of how it might be true. Perhaps it will be thought unreasonable
to require such a conception as a condition of understanding. After all, it
might be said, the meaning of physicalism is clear enough: mental states are
states of the body; mental events are physical events. We do not know which
physical states and events they are, but that should not prevent us from
understanding the hypothesis. What could be clearer than the words 'is' and
'are'? But
I believe it is precisely this apparent clarity of the word 'is' that is
deceptive. Usually, when we are told that X is Y we know how
it is supposed to be true, but that depends on a conceptual or theoretical
background and is not conveyed by the 'is' alone. We know how both "X"
and "Y " refer, and the kinds of
things to which they refer, and we have a rough idea how the two referential
paths might converge on a single thing, be it an object, a person, a process,
an event or whatever. But when the two terms of the identification are very disparate
it may not be so clear how it could be true. We may not have even a rough
idea of how the two referential paths could converge, or what kind of things
they might converge on, and a theoretical framework may have to be supplied
to enable us to understand this. Without the framework, an air of mysticism
surrounds the identification. This
explains the magical flavor of popular presentations of fundamental
scientific discoveries, given out as propositions to which one must subscribe
without really understanding them. For example, people are now told at an
early age that all matter is really energy. But despite the fact that -'they
know what 'is' means, most of them never form a conception of what makes this
claim true, because they lack the theoretical background. At
the present time the status of physicalism is similar to that which the
hypothesis that matter is energy would have had if uttered by a pre-Socratic philosopher. We do not have the beginnings of a conception
of how it might be true. In order to understand the hypothesis that a mental
event is a physical event, we require more than an understanding of the word
'is'. The idea of how a mental and a physical term might refer to the same
thing is lacking, and the usual analogies with theoretical identification in
other fields fail to supply it. They fail because if we construe the
reference of mental terms to physical events on the usual model, we either
get a reappearance of separate subjective events as the effects through which
mental reference to physical events is secured, or else we get a false
account of how mental terms refer (for example, a causal behaviorist one). Strangely
enough, we may have evidence for the truth of something we cannot really
understand. Suppose a caterpillar is locked in a sterile safe by someone
unfamiliar with insect metamorphosis, and weeks later the safe is reopened,
revealing a butterfly. If the person knows that the safe has been shut the
whole time, he has reason to believe that the butterfly is or was once the
caterpillar, without having any idea in what sense this might be so. (One
possibility is that the caterpillar contained a tiny winged parasite that
devoured it and grew into the butterfly.) It
is conceivable that we are in such a position with regard to physicalism.
Donald Davidson has argued that if mental events have physical causes and
effects, they must have physical descriptions. He holds that we have reason
to believe this even though we do not—and in fact could not—have a
general psychophysical theory.12 His argument applies to
intentional mental events, but I think we also have some reason to believe
that sensations are physical processes, without being in a position to
understand how. Davidson's position is that certain physical events have irreducibly
mental properties, and perhaps some view describable in this way is correct.
But nothing of which we can now form a conception corresponds to it; nor have
we any idea what a theory would be like that enabled us to conceive of it.13
Very
little work has been done on the basic question (from which mention of the
brain can be entirely omitted) whether any sense can be made of experiences'
having an objective character at all. Does it make sense, in other words, to
ask what my experiences are really like, as opposed to how they appear
to me? We cannot genuinely understand the hypothesis that their nature is
captured in a physical description unless we understand the more fundamental
idea that they have an objective nature (or that objective processes can
have a subjective nature).14 I
should like to close with a speculative proposal. It may be possible to
approach the gap between subjective and objective from another direction.
Setting aside temporarily the relation between the mind and the brain, we can
pursue a more objective understanding of the mental in its own right. At
present we are completely unequipped to think about the subjective character
of experience without relying on the imagination—without taking up the point
of view of the experiential subject. This should be regarded as a challenge
to form new concepts and devise a new method—an objective phenomenology not
dependent on empathy or the imagination. Though presumably it would not
capture everything, its goal would be to describe, at least in part, the
subjective character of experiences in a form comprehensible to beings
incapable of having those experiences. We
would have to develop such a phenomenology to describe the sonar experiences
of bats; but it would also be possible to begin with humans. One might try,
for example, to develop concepts that could be used to explain to a person
blind from birth what it was like to see. One would reach a blank wall
eventually, but it should be possible to devise a method of expressing in
objective terms much more than we can at present, and with much greater
precision. The loose intermodal analogies—for example, 'Red is like the sound
of a trumpet'—which crop up in discussions of this subject
are of little use. That should be clear to anyone who has both heard a
trumpet and seen red. But structural features of perception might be more
accessible to objective description, even though something would be left out.
And concepts alternative to those we learn in the first person may enable us
to arrive at a kind of understanding even of our own experience which is
denied us by the very ease of description and lack of distance that
subjective concepts afford. Apart
from its own interest, a phenomenology that is in this sense objective may
permit questions about the physically basis of experience to assume a more
intelligible form. Aspects of subjective experience that admitted this kind
of objective description might be better candidates for objective
explanations of a more familiar sort. But whether or not this guess is
correct, it seems unlikely that any physical theory of mind can be
contemplated until more thought has been given to the general problem of
subjective and objective. Otherwise we cannot even pose the mind-body problem
without sidestepping it. NOTES: 1
Examples are J. J. C. Smart, Philosophy and Scientific Realism
(London: Routledge & Kegan
Paul, 1963); David K. Lewis, 'An Argument for the Identity Theory', Journal
of Philosophy, LXIII (1966), reprinted with addenda in David M.
Rosenthal, Materialism & the Mind-Body Problem, (Engelwood Cliffs, NJ.: Prentice-Hall, 1971); Hilary
Putnam, 2
Perhaps there could not actually be such robots. Perhaps anything complex
enough to behave like a person would have experiences. But that, if true, is
a fact which cannot be discovered merely by analyzing the concept of
experience. 3 It
is not equivalent to that about which we are incorrigible, both because we
are not incorrigible about experience and because experience is present in
animals lacking language and thought, who have no beliefs at all about their
experiences. 4 Cf.
Richard Rorty, 'Mind-Body Identity, Privacy, and
Categories', Review of Metaphysics, XIX (1965), esp. 37-8. 5 By 'our
own case' I do not mean just 'my own case', but rather the mentalistic ideas that we apply unproblematically
to ourselves and other human beings. 6 Therefore
the analogical form of the English expression 'what it is like' is
misleading. It does not mean 'what (in our experience) it resembles',
but rather 'how it is for the subject himself'. 7 Any
intelligent extraterrestrial beings totally different from us. 8 It
may be easier than I suppose to transcend inter-species barriers with the aid
of the imagination. For example, blind people are able to detect objects near
them by a form of sonar, using vocal clicks or taps of a cane. Perhaps if one
knew what that was like, one could by extension imagine roughly what it was
like to possess the much more refined sonar of a bat. The distance between
oneself and other persons and other species can fall anywhere on a continuum.
Even for other persons the understanding of what it is like to be them is
only partial, and when one moves to species very different from oneself, a
lesser degree of partial understanding may still be available. The
imagination is remarkably flexible. My point, however, is not that we cannot know
what it is like to be a bat. I am not raising that epistemological problem.
My point is rather that even to form a conception of what it is like
to be a bat (and a fortiori to know what it is like to be a bat) one
must take up the bat's point of view. If one can take it up roughly, or
partially, then one's conception will also be rough or partial. Or so it
seems in our present state of understanding. 9 The
problem I am going to raise can therefore be posed even if the distinction
between more subjective and more objective descriptions or viewpoints can
itself be made only within a larger human point of view. I do not accept this
kind of conceptual relativism, but it need not be refuted to make the point
that psychophysical reduction cannot be accommodated by the
subjective-to-objective model from other cases. 10 The
problem is not just that when I look at the Mona Lisa, my visual
experience has a certain quality, no trace of which is to be found by someone
looking into my brain. For even if he did observe there a tiny image of the Mona
Lisa, he would have no reason to identify it with the experience. 11 The
relation would therefore not be a contingent one, like that of a cause and
its distinct effect. It would be necessarily true that a physical state felt
a certain way. Saul Kripke in Semantics of
Natural Language, (ed. Davidson and Harman) argues that causal
behaviorist and related analyses of the mental fail because they construe,
e.g., 'pain' as a merely contingent name of pains. The subjective character
of an experience ('its immediate phenomenolocal
quality' Kripke calls it (p. 340)) is the essential
property left out by such analyses, and the one in virtue of which it is, necessarily,
the experience it is. My view is closely related to his. Like Kripke, I find the hypothesis that a certain brain state
should necessarily have a certain subjective character incomprehensible
without further explanation. No such explanation emerges from theories which
view the mind-brain relation as contingent, but perhaps there are other
alternatives, not yet discovered. A
theory that explained how the mind-brain relation was necessary would still
leave us with Kripke's problem of explaining why it
nevertheless appears contingent. That difficulty seems to me surmountable, in
the following way. We may imagine something by representing it to ourselves
either perceptually, sympathetically, or symbolically. I shall not try to say
how symbolic imagination works, but part of what happens in the other two
cases is this. To imagine something perceptually, we put ourselves in a
conscious state resembling the state we would be in if we perceived it. To
imagine something sympathetically, we put ourselves in a conscious state
resembling the thing itself. (This method can be used only to imagine mental
events and stares—our own or another's.) When we try to imagine a mental
state occurring without its associated brain state, we first sympathetically
imagine the occurrence of the mental state: that is, we put ourselves into a
state that resembles it mentally. At the same time, we attempt perceptually
to imagine the nonoccurrence of the associated physical state, by putting
ourselves into another state unconnected with the first; one resembling that
which we would be in if we perceived the nonoccurrence of the physical state.
Where the imagination of physical features is perceptual and the imagination
of mental features is sympathetic, it appears to us that we can imagine any
experience occurring without its associated brain state, and vice versa. The
relation between them will appear contingent even if it is necessary, because
of the independence of the disparate types of imagination. (Solipsism
incidentally, results if one misinterprets sympathetic imagination as if it
worked like perceptual imagination: it then seems impossible to imagine any
experience that is not one's own.) 12 See
'Mental Events' in Experience and Theory, ed. Lawrence Foster and J.
W. Swanson (Amherst: University of Massachusetts Press, 1970); though I do
not understand the argument against psychophysical laws. 13 Similar
remarks apply to my paper 'Physicalism', Philosophical Review, LXXIV
(1965), 339-56, reprinted with postscript in Modern Materialism, ed.
John O'Connor (New York: Harcourt Brace Jovanovich, 1969). 14
This question also lies at the heart of the problem of other minds, whose
close connection with the mind-body problem is often overlooked. If one
understood how subjective experience could have an objective nature, one
would understand the existence of subjects other than oneself. 15 I
have not defined the term 'physical'. Obviously it does not apply just to
what can be described by the concepts of contemporary physics, since we
expect further developments. Some may think there is nothing to prevent
mental phenomena from eventually being recognized as physical in their own
right. But whatever else may be said of the physical, it has to be objective.
So if our idea of the physical ever expands to include mental phenomena, it
will have to assign them an objective character—whether or not this is done
by analyzing them in terms of other phenomena already regarded as physical It
seems to me more likely, however, that mental-physical relations will
eventually be expressed in a theory whose fundamental terms cannot be placed
clearly in either category. |
