Unphilosophical Introduction: What Concepts Have To Be

THIS is a book about concepts. Two of its main theses are:
—that if you are going to run a representational/computational theory
of mind (that is, any version of RTM; see Chapter 1) you will need
a theory of concepts.
And:
—that none of the theories of concepts that are currently taken at all
seriously either in cognitive science or in philosophy can conceivably
fill the bill.
To argue this, I shall first need to say what bill it is that needs to be filled.
That’s the burden of this chapter. I want to set out five conditions that an
acceptable theory of concepts would have to meet. Several chapters
following this one will be devoted to making clear by how much, and for
what reasons, current theories of concepts fail to meet them.
A word about the epistemic status of the conditions I’m about to
endorse: I regard them as fallible but not negotiable. Not negotiable, that
is, short of giving up on RTM itself; and RTM remains the only game in
town, even after all these years. In effect, I’m claiming that these
constraints on concepts follow just from the architecture of RTMs
together with some assumptions about cognitive processes and capacities
which, though certainly contingent, are none the less hardly possible to
doubt. (I mean, of course, hardly possible to doubt really, not hardly
possible to doubt philosophically.) If this is indeed the status of these
constraints, then I think we had better do what we can to construct a
theory of concepts that satisfies them.
So, then, here are my five not-negotiable conditions on a theory of
concepts.
1. Concepts are mental particulars; specifically, they satisfy whatever
ontological conditions have to be met by things that function as
mental causes and effects.
Since this is entailed by RTM (see Chapter 1), and hence is common to all
the theories of concepts I’ll consider, I won’t go on about it here. If,
however, you think that intentional causation explains behaviour only in
the way that the solubility of sugar explains its dissolving (see Ryle 1949),
or if you think that intentional explanations aren’t causal at all (see e.g.
Collins 1987 ), then nothing in the following discussion will be of much use
to you, and I fear we’ve reached a parting of the ways. At least one of us
is wasting his time; I do hope it’s you.
2. Concepts are categories and are routinely employed as such.
To say that concepts are categories is to say that they apply to things in the
world; things in the world ‘fall under them’. So, for example, Greycat the
cat, but not Dumbo the elephant, falls under the concept CAT. Which,
for present purposes, is equivalent to saying that Greycat is in the extension
of CAT, that ‘Greycat is a cat’ is true, and that ‘is a cat’ is true of Greycat.
I shall sometimes refer to this galaxy of considerations by saying that
applications of concepts are susceptible of ‘semantic evaluation’: claims, or
thoughts, that a certain concept applies to a certain thing are always
susceptible of evaluation in such semantical terms as satisfied/unsatisfied,
true/false, correct/incorrect, and the like. There are, to be sure, issues about
these various aspects of semantic evaluability, and about the relations
among them, that a scrupulous philosopher might well wish to attend to.
But in this chapter, I propose to keep the philosophy to a bare minimum.1
Much of the life of the mind consists in applying concepts to things. If
I think Greycat is a cat (de dicto, as it were), I thereby apply the concept
CAT to Greycat (correctly, as it happens). If, looking at Greycat, I take
him to be a cat, then too I apply the concept CAT to Greycat. (If looking
at Greycat I take him to be a meatloaf, I thereby apply the concept
MEATLOAF to Greycat; incorrectly, as it happens.) Or if, in reasoning
about Greycat, I infer that since he’s a cat he must be an animal, I thereby
proceed from applying one concept to Greycat to the licensed application
of another concept; the license consisting, I suppose, in things I know
about how the extensions of the concepts CAT and ANIMAL are related.
In fact, RTM being once assumed, most of cognitive psychology,
including the psychology of memory, perception, and reasoning, is about
how we apply concepts. And most of the rest is about how we acquire the
concepts that we thus apply. Correspondingly, the empirical data to which
cognitive psychologists are responsible consist largely of measures of
subject performance in concept application tasks. The long and short is:
whatever else a theory of concepts says about them, it had better exhibit
1 Or, at least, to confine it to footnotes.
concepts as the sorts of things that get applied in the course of mental
processes. I take it that consensus about this is pretty general in the
cognitive sciences, so I won’t labour it further here.
Caveat: it’s simply untendentious that concepts have their satisfaction
conditions essentially. Nothing in any mental life could be the concept
CAT unless it is satisfied by cats. It couldn’t be that there are some mental
lives in which the concept CAT applies to CATS and others in which it
doesn’t. If you haven’t got a concept that applies to cats, that entails that
you haven’t got the CAT concept. But though the satisfaction conditions
of a concept are patently among its essential properties, it does not follow
that the confirmation conditions of a concept are among its essential
properties. Confirmation is an epistemic relation, not a semantic relation,
and it is generally theory mediated, hence holistic. On the one hand, given
the right background theory, the merest ripple in cat infested waters might
serve to confirm an ascription of cathood; and, on the other hand, no catcontaining
layout is so well lit, or so utterly uncluttered, or so selfcertifying
that your failure to ascribe cathood therein would entail that
you lack the concept. In short, it is OK to be an atomist about the
metaphysical conditions for a concept’s having satisfaction conditions
(which I am and will try to convince you to be too), and yet be a holist
about the confirmation of claims that a certain concept is satisfied in a
certain situation. Shorter still: just as Quine and Duhem and those guys
taught us, there aren’t any criteria. So at least I shall assume throughout
what follows.
3. Compositionality: concepts are the constituents of thoughts and, in
indefinitely many cases, of one another. Mental representations
inherit their contents from the contents of their constituents.
Some terminology: I’ll use ‘thoughts’ as my cover term for the mental
representations which, according to RTMs, express the propositions that
are the objects of propositional attitudes. Thus, a belief that it will rain and
a hope that it will rain share a thought as well as a proposition which that
thought expresses. For present purposes, it will do to think of thoughts as
mental representations analogous to closed sentences, and concepts as
mental representations analogous to the corresponding open ones. It may
strike you that mental representation is a lot like language, according to my
version of RTM. Quite so; how could language express thought if that
were not the case?
Qua constituents of thoughts, and of each other, concepts play a certain
role in explaining why the propositional attitudes are productive and
systematic. The outlines of this story are well known, though by no means
untendentious: