I was recently reading a fascinating book by Nancy
Cartwright -The Dappled World- (highly
recommended for philo of science aficionados) in which she contrasts the role of
powers/natures/capacities versus regularities in scientific theory. The classical empiricist/Humean tradition rejected
the former as occult residues of an earlier search for Aristotelian essences and
insisted on founding all scientific knowledge on “the kinds of qualities that
appear to us in experience (79)” (recall the dictum: nothing in the intellect
that is not first in the senses!). Modern empiricists/Humeans endorse this
antipathy to “powers” by treating the laws of nature as summaries of “what
things do (82).” Cartwright contrasts this with the view that laws are about powers/natures/capacities,
which is not about what things do but “what it is in their nature to do (82).” Here’s
a quote that provides a good feel for what she has in mind:
What we have done in modern
science, as I see it, is to break the connection between what the explanatory
nature is- what it is in and of itself- and what it does. An atom in an excited
state, when agitated, emits photons and produces light. It is, I say, in the
nature of an excited atom to produce light. Here the explanatory feature –an
atom’s being in an excited state- is a structural feature of the atom…For
modern science what something really is -how it is defined and identified- and
what it is in its nature to do are separate things.
In short, there is an important metaphysical distinction that
divides Empiricists and Rationalists. For the former the laws of nature are in
effect summaries (perhaps statistical) of “actually exhibited behaviors”, for
the latter they describe abstract “configurations of properties” or
“structures.” These latter underlie, but are distinct from, behavior (“what
appears on the surface”), these being “the result of the complex interaction of
natures (81).”
Cartwright notes the close connection between the
Rationalist conception of powers/natures/capacities and the analytic method of
inquiry characteristic of the physical sciences, often called “Galilean
idealization.” She also provides several interesting reasons for insisting on
the distinction between what something is versus what it does. Here are two.
First, given that visible behavior is an interaction effect
of complex natures it is often impossible to actually see the contribution of
the power one is interested in, even in the very contrived circumstances of
controlled experiments. She illustrates this using Coulomb’s law and the
interfering effects of gravity. As she points out:
Coulomb’s law tells not what force
charged particles experience but rather what it is in their nature, qua charged, to experience…What
particles that are both massive and charged actually experience will depend on what
tendency they have qua charged and
what qua massive (82).
Thus, actual measurable forces are the result of the
interaction of several powers and it takes great deal of idealization,
experimentation, calculation and inference to (a) simply isolate the effects of
just one and segregate it from
everything else, viz. to find out how two charged bodies “ ‘would interact if
their masses were zero.’ ”[1]
And (b) to use the results from (a) to
find out what the actual powers involved are:
The ultimate aim is to find out how
the charged bodies interact not when their masses are zero, nor under any other
specific set of circumstances, but
how they interact qua charged.
Second, contrary to the accepted wisdom more often than not
in the real world the same cause is not followed
by the same effect. In fact, generating
stable relations between cause and effect requires very careful contrivance in
manufactured artificial experimental settings.
Cartwright refers to these as nomological engines; set-ups that allow
for invariant regular connections between what powers/natures/capacities can do and what they actually do. Except
in such settings the Humean dictum that effects regularly follow causes is
hardly apparent.
Outside the supervision of a
laboratory or the closed casement of a factory-made module, what happens in one
instance is rarely a guide to what will happen in others. Situations that lend themselves to
generalizations are special…(86).
Now, the punch line: Cartwright’s
discussion should sound familiar to generative ears. Chomsky’s important distinction
between competence and performance is a rationalist one. UG is a theory of human linguistic
powers/natures/capacities, not a theory of linguistic behavior. UG is not a summary of behavioral regularities.
Indeed, linguistic behavior is a very complex interaction effect with competence
being one of many (very poorly understood) factors behind it. The distinction
between what a speaker knows (competence) and what a speaker puts this
knowledge to use (performance) echoes Cartwright’s rationalist themes.
Similarly, the rejection of the idea that linguistic competence is just (a
possibly fancy statistical) summary of behavior should be recognized as the
linguistic version of the general Rationalist endorsement of the distinction
between powers/natures/capacities and their behavioral/phenomenal effects.
Lastly, the Rationalist conception buttresses a reasonable skepticism against a currently
common (and sadly fashionable) view that language acquisition is largely a statistical exercise where
minds track environmental regularities, a view more congenial with the
empiricist conception that identifies what something is with what it does. This
cannot be true: for there are precious few such regularities in the wild and what there is won't (in fact cannot) alone reveal
the powers, capacities and natures of the underlying object of linguistic interest,
i.e. the fine structure of UG.
[1]
Cartwright observes that though doing (1) is difficult it is “just a stage; in
itself this information is uninteresting.” (83-4), a point not unlike that made in a previous post.
