Prototypes and Compositionality 115

But I do want to say a word or so about the second objection, which is
that holism about content individuation doesn’t square with key principles
of the theory theory itself. Consider, in particular, the idea that new
concepts get introduced, in the course of theory change, by a kind of
implicit theoretical definition. In all the examples I’ve heard of, a theory
can be used to effect the implicit definition of a new term only if at least
some of its vocabulary is isolated from meaning changes of the sorts that
holists say that concept introduction brings about. That’s hardly
surprising. Intuitively, implicit definition determines the meaning of a new
term by determining its inferential relations to terms in the host theory
that are presumed to be previously understood. It is, to put it mildly, hard to
see how this could work if introducing a new concept into a theory ipso
facto changes what all the old terms mean. For then the expressions by
reference to which the neologism is introduced aren’t ‘previously
understood’ after all: they are just homophones of the previously
understood expressions.22
Consider, for a familiar example, the introduction by implicit definition
of a logical constant like ‘Ú’. The idea is that to determine that ‘Ú’ has the
same sense as the (truth conditional, inclusive) English ‘or’, it’s sufficient
to stipulate that:
P ® P Ú Q
(P Ú Q) & ~P ® Q
But the plausibility of claiming that these stipulations determine that ‘Ú’
means ‘or’ depends on supposing that they preserve the standard
interpretations of ‘&’ (= conjunction), ‘~’ (= negation), and ‘®’ (= truthfunctional
implication). That, however, implies that the interpretation of
‘&’, ‘~’, and ‘®’ must be assumed to be isolated from whatever meaning
changes adding ‘Ú’ to the host theory is supposed to bring about; an
assumption that is contrary, apparently, to the holist thesis that the
semantic effects of theory change reverberate throughout the vocabulary
of the theory. (I say that it’s ‘apparently’ contrary to the holist thesis
because I know of no formulation of semantic holism that is precise
enough to yield unequivocal entailments about which changes of theory
effect which changes of meaning.)
Prototypes and Compositionality 115
22 This point is related, but not identical, to the familiar worry about whether implicit
definition can effect a ‘qualitative change’ in a theory’s expressive power: the worry that
definitions (implicit or otherwise) can only introduce concepts whose contents are already
expressible by the host theory. (For discussion, see Fodor 1975.) It looks to me that implicit
definition is specially problematic for meaning holists even if it’s granted that an implicit
definition can (somehow) extend the host theory’s expressive power.
This isn’t just a technical problem; texts that flout it tend to defy
coherent exegesis. Consider, for one example among very many, Gopnik’s
suggestion23 that
An ‘object’ is a theoretical entity which explains sequences of what (for lack of a
better term) we might call object-appearances at the evidential level . . . At the very
earliest stage infants seem to have a few rules about the relations between their own
actions and object-appearances, for example, infants seem to know that objects
disappear when you turn away from them and reappear when you turn back to
them. (1988: 205)
(and so forth, mutatis mutandis, for further ‘rules’ that the child gets later).
How are we to interpret this passage? Notice the tell-tale aporia (where
are you, Jacques Derrida, now that we need you?). The rule with which the
infants are credited is said to be about “relations between their own actions
and object-appearances” (my emphasis). But, when an instance of such a
rule is offered, it turns out to be that “objects [my emphasis] disappear
when you turn away from them”. Question: what does ‘objects’ mean in
this rule? In particular, what does it mean to the infant who, we’re
supposing, learns the concept OBJECT by a process that involves
formulating and adopting the rule?24 If it means object-appearances, then
(quite aside from traditional worries about how an appearance could
reappear) it doesn’t do what Gopnik wants; since it specifies a relation
among object-appearances, it doesn’t give the infant information about
the relation between objects and object-appearances.
So, maybe ‘object’ means theoretical entity which explains sequences of
what (for lack of a better term) we might call object-appearances at the
evidential level. I rush past the implausibility of claiming that infants have
to have that much ontology (in particular, that much dubious ontology) in
order to learn quotidian object-concepts like CHAIR. I’m a nativist too,
after all. The more pressing problem for a theory theorist is: if that’s what
‘object’ means in the infant’s rule, in what sense are there discontinuities in
the development of the infant’s object-concept ? On this reading of the text,
it looks like what the infant has—right from the start and right to the
finish—is a concept of an object that’s much like Locke’s: objects are
unobservable kinds of things that cause experiences. Correspondingly,
cognitive development consists of learning more and more about things of
116 Prototypes and Compositionality
23 I don’t particularly mean to pick on Gopnik; the cognitive science literature is full of
examples of the mistake that I’m trying to draw attention to.What’s unusual about Gopnik’s
treatment is just that it’s clear enough for one to see what the problem is.
24 As usual, it’s essential to keep in mind that when a de dicto intentional explanation
attributes to an agent knowledge (rules, etc.), it thereby credits the agent with the concepts
involved in formulating the knowledge, and thus incurs the burden of saying what concepts
they are. See the ‘methodological digression’ in Chapter 2.
this kind (e.g. that when you turn your back on one, it ceases to cause
appearances in you . . . etc.).25What, then, has become of the discontinuity
of the object-concept? In particular, what’s become of the incommensurability
of the infant’s object-concept with grown-up Gopnik’s? It turns out
that Gopnik can, after all, say exactly what (according to her theory) the
infant’s earliest concept of an object is: it’s the concept of a theoretical
entity which explains sequences of . . . etc. . . . and which ceases to cause
appearances in you when you turn your back on it . . . etc.
I suppose what Gopnik really ought to say, if she wants to be true to the
implicit definition picture, is that the concept of an object is that of ‘AN
X WHICH . . .’, and that cognitive development consists in adding more
and more relative clauses. But it’s hard to see why such a thesis would
count as construing concept development as discontinuous. And, anyhow,
it’s hard to see how it could be swallowed by a meaning holist. Isn’t
meaning holism, by definition, committed to there not being a notion of
content identity that tolerates the addition of new information to the same
old concept?
The local moral, to repeat, is that maybe you can make sense of concept
introduction as implicit theoretical definition, and maybe you can make
sense of meaning holism. But it’s very unclear that you can make sense of
both at the same time. The general moral is that, if the theory theory has
a distinctive and coherent answer to the ‘What’s a concept?’ question on
offer, it’s a well-kept secret.
I should add, in minimal fairness, that it’s not clear that theory theorists
are really all that interested in what concepts are. Certainly it’s often hard
to tell whether they are from what they say. For example, Medin and
Wattenmaker (1987; see also Murphy and Medin 1985) undertake to
“review evidence that suggests concepts should be viewed as embedded in
theories” (34–5), a thesis which they clearly regard as tendentious, but
which, as it is stated, it’s hard to imagine that anyone could disagree with.
What I suppose they must have in mind is that concepts are somehow
constituted (their identity is somehow determined) by the theories in which
they are embedded. But that claim, though tendentious enough, doesn’t
amount to a new account of conceptual content; unless the ‘somehows’ are
somehow cashed, it just reiterates IRS.
The situation in Medin and Wattenmaker is especially confusing
because its so hard to figure out what they think that the theory theory is
a theory of; they are explicit that it’s supposed to provide an account of the
Prototypes and Compositionality 117
25 If “object” means thing that causes appearances then, of course, the rule isn’t that
objects disappear when you turn your back on them; it’s just that they cease, for the nonce,
to cause you to experience them.