98 J.J. Haldane
identity but composition. Actions are more than movements; persons are
more than bodies. Eliminativists and other reductive materialists are led to
suppose otherwise because they bring to the issue a prior presumption that all
there is, and so all that can be involved, is matter in the physicalist sense.
Let me note here that while Smart is certainly a materialist he does not,
I believe, go along with those who claim that it is possible, in principle, to
give definitional or deductive equivalents of psychological terms, and nor does
he agree with Churchland that psychological descriptions can be eliminated.
His view is that notwithstanding the impossibility of reductions or eliminations
it is plausible to hold that there are no genuine mental properties, no features
over and above those acknowledged by physics. How can someone defend
such a view? After all if it is allowed that talk of beliefs, desires, intentions
and so on is appropriate, and that it is not equivalent to talk about physical
states, is this not reason to acknowledge that there are irreducible psycholo-
gical attributes? Indeed, does it not involve an implicit commitment to the
reality of the mental as a distinct category?
If I have him aright, Smart’s view is that some kind of property dualism or
mental emergentism would be the appropriate conclusion were it not for
other considerations. More precisely, he believes, first, that the circumstances
in which we find ourselves attributing psychological states to one another,
and the styles of those attributions, encourage an identification of the former
with states of the brain; and second, that we have reasons not to posit non-
physical properties, these being the sufficiency of physics and the difficulty of
reconciling other sorts of facts and explanations with it.
In discussing the problem of evil towards the end of chapter 1 Smart
describes and defends determinism. I shall have reason to come back to both
issues later; for now, however, I want to pick up what he has to say about the
explanation of actions. In keeping with a widely shared view he holds that in
citing an agent’s reasons we are giving causesof his actions. This will seem to
support the identification of psychological with physical states if we also
assume that the brain fits into the explanation of behaviour in a similar way.
Let us suppose Kirsty wrote her sentence becauseshe wanted to communicate
her ideas. In writing it her body moved in various ways becauseof events in
her brain and nervous system. Putting these two together we might con-
clude that there was one sequence of behaviour, describable psychologically
and physiologically, and one cause (or subset of causes), specified in the first
case by talk of reasons and in the second by talk of events in the central
nervous system. This inference constitutes the first of the considerations against
property dualism. The second is less an argument than an extended assump-
tion. It is that physics is all we need and that since the recognition of any
other kind of reality would ex hypothesi be inexplicable physicalistically, it
would be at odds with physics.