APPENDIX 5B The ‘Theory Theory’18 of Concepts

APPENDIX 5B
The ‘Theory Theory’18 of Concepts
The theories of concepts discussed so far all presuppose Inferential Role
Semantics, so they all owe an account of which inferences determine
conceptual content. The big divides are between holism (which says that
all inferences do) and some sort of molecularism (which says that only
some inferences do); and, within the latter, between classical theories
(according to which it is modality that matters to content constitution)
and prototype theories (according to which it’s empirical reliability that
does). In effect, the various theories of concepts we’ve reviewed are
versions of IRS distinguished, primarily, by what they say about the
problem of individuating content.
Now, a quite standard reading of the history of cognitive science has
the reliability-based versions of IRS displacing the modality-based
versions and in turn being displaced, very recently, by theory theories.19
But that way of telling the story is, I think, mistaken. Though theory
theories do propose a view about what concepts are (or, anyhow, about
what concepts are like; or, anyhow, about what a lot of concepts are like),
they don’t, as far as I can tell, offer a distinct approach to the content
individuation problems. Sometimes they borrow the modality story from
definitional theories, sometimes they borrow the reliability story from
prototype theories, sometimes they share the holist’s despair of
individuating concepts at all. So, for our purposes at least, it’s unclear that
theory theories of concepts differ substantially from the kinds of theories
112 Prototypes and Compositionality
18 I’m not crazy about this terminology, if only because it invites conflation with the
quite different issue whether “folk psychology” is a (tacit) theory (see, for example, Gordon
1986). But it’s standard in the cognitive science literature so I’ll stick with it, and from here
on I’ll omit the shudder-quotes.
19 For a relatively clear example of a discussion where theory theories are viewed as
alternatives to probabilistic accounts of concepts, see Keil 1987. See also Keil 1991, where
the primary contrast is between theory theories and “associative” models of concept
structure. For a critical survey of the recent history, see Margolis 1994.
of concepts that we’ve already reviewed. Hence the relatively cursory
treatment they’re about to receive.
The basic idea is that concepts are like theoretical constructs in science
as the latter are often construed by post-Empiricist philosophers of science.
The caveat is important. For example, it’s not unusual (see Carey 1991;
Gopnik 1988) among theory theorists to postulate ‘stage-like discontinuities’
in conceptual development, much as Piagetians do. But, unlike
Piaget, theory theorists construe the putative stage changes on the analogy
of—perhaps even as special cases of—the kinds of discontinuities that
‘paradigm shifts’ are said to occasion in the history of science. The usual
Kuhnian morals are often explicitly drawn:
the concepts of the new and old theory and of the evidential description are
incommensurab[le].(Gopnik 1988: 199)
Asking whether or not the six-month-old has a concept of object-permanence in
the same sense that the 18-month-old does is like asking whether or not the
alchemist and the chemist have the same concept of gold, or whether Newton had
the same concept of space as Einstein. These concepts are embedded in complex
theories and there is no simple way of comparing them. Moreover, particular
concepts are inextricably intertwined with other concepts in the theory. (Ibid.:
205)
It should be clear how much this account of conceptual ontogenesis
relies on a Kuhnian view of science. It isn’t just that if Kuhn is wrong
about theory change, then Gopnik is wrong about the analogy between the
history of science and conceptual development. It’s also that key notions
like discontinuity and incommensurability aren’t explicated within the
ontogenetic theory; the buck is simply passed to the philosophers. “It may
not resolve our puzzlement over the phenomena of qualitative conceptual
change in childhood to point out that there are exactly parallel paradoxes
of incommensurability in science, but at this stage we may see the
substitution of a single puzzling phenomenon for two separate puzzling
phenomena as some sort of progress” (Gopnik 1988: 209). Correspondingly,
however, if you find the idea that a scientific theory-change is a
paradigm shift less than fully perspicuous, you will also be uncertain what
exactly it is that the ontogenetic analogy asserts about stages of conceptual
development. Your response will then be a sense less of illumination than
of déjà vu.
If Gopnik finds some solace in this situation, that’s because, like Kuhn,
she takes IRS not to be in dispute.20 The putative “problem of incommens-
Prototypes and Compositionality 113
20 They aren’t the only ones, of course. For example, Keil remarks that “Theories . . .
make it impossible . . . to talk about the construction of concepts solely on the basis of
urability” is that if the vocabulary of a science is implicitly defined by the
theories it endorses, it’s hard to see how the theories can correct or
contradict each other. This state of affairs might be supposed to provide
a precedent for psychologists to appeal to who hold that the minds of
young children are incommensurably different from the minds of adults.
Alternatively, it might be taken as a reductio of the supposition that the
vocabulary of a science is implicitly defined by its theories. It’s hard to say
which way one ought to take it barring some respectable story about how
scientific theories implicitly define their vocabularies; specifically, an
account that makes clear which of the inferences that such a theory
licenses are constitutive of the concepts it deploys. And there’s no point in
cognitive scientists relying on the philosophy of science for an answer to
this question; the philosophy of science hasn’t got one. It seems that we’re
back where we started.
In short, it may be that the right moral to draw from the putative
analogy between scientific paradigms and developmental stages is that the
ontogenesis of concepts is discontinuous, just like scientific theory-change.
Or the right moral may be that, by relativizing the individuation of
concepts to the individuation of theories, IRS makes a hash of both
cognitive development and the history of science.
If there is any positive account of conceptual content that most theory
theorists are inclined towards, I suppose that it’s holism.21 I don’t, however,
know of any attempt they have made seriously to confront the objections
that meaning holism is prone to. Two of these are particularly relevant.
The first is familiar and quite general (see Chapter 1 and Fodor and
Lepore 1992) and I won’t go on about it here. Suffice it that if the
individuation of concepts is literally relativized to whole belief systems,
then no two people, and no two time slices of a given person, are ever
subsumed by the same intentional generalizations, and the prospects for
robust theories in intentional psychology are negligible.
114 Prototypes and Compositionality
probabilistic distributions of properties in the world” (1987: 196). But that’s true only on the
assumption that theories somehow constitute the concepts they contain. Ditto Keil’s remark
that “future work on the nature of concepts . . . must focus on the sorts of theories that
emerge in children and how these theories come to influence the structure of the concepts
that they embrace” (ibid.).
21 There are exceptions. Susan Carey thinks that the individuation of concepts must be
relativized to the theories they occur in, but that only the basic ‘ontological’ commitments
of a theory are content constitutive. (However, see Carey 1985: 168: “I assume that there is
a continuum of degrees of conceptual differences, at the extreme end of which are concepts
embedded in incommensurable conceptual systems.”) It’s left open how basic ontological
claims are to be distinguished from commitments of other kinds, and Carey is quite aware
that problems about drawing this distinction are depressingly like the analytic/synthetic
problems. But in so far as Carey has an account of content individuation on offer, it does
seem to be some version of the Classical theory.