C CUNYB/Clarke December, :
AFabulous World (–) which violently moves its finer parts and separates them from the larger
ones, I find that this alone could cause it [the wood] to undergo all the
same changes which are observed when it burns’ (xi.). If we are forced
to hypothesize what properties wood has, in virtue of which it gives off
light when it burns, it is a short step to acknowledge that we could not
possiblyexplainthe phenomenon of burning and emitting light simply
by attributing to the wood precisely those features that we set out to
explain.
Later writers almost competed with each other to construct persua-
sive examples of this insight. Boyle argued, for example, that we cannot
explain how a key opens a particular lock by ascribing to the key a ‘lock
opening’ form. This argument was developed by later Cartesians, espe-
cially by Jacques Rohault (–), into a refrain about the emptiness
of pretending to explain some event or phenomenon by attributing to it
just those features for which the explanation was originally sought. One
of the most famous examples, adapted by Moli`ere and assigned to Doctor
Bachelierus inLe Malade imaginaire, mocked the suggestion that one
could explain how sleeping powder has its desired effect by saying that it
has a ‘dormitive power’.
These complementary conclusions – about the invalidity of attributing
qualities that resemble our sensations to the phenomena that cause them,
and about the failure of scholastic forms and qualities to explain anything –
implied that, when faced with explaining even such a familiar phenomenon
as the experience of light, we have no choice but to guess at the nature of
the reality in question. The kind of guesswork that Descartes was willing
to tolerate was limited to those features of things that were both familiar
and well understood, such as the size, shape, and movement of pieces of
matter, and the whole project was inspired by a model that was borrowed
from our understanding of machines.
Within a few short paragraphs, therefore, Descartes had proposed rele-
gating the whole complex scholastic network of prime matter, forms, and
qualities to a failed enterprise, and substituting hypothetical models that
assume nothing more than the size, shape, arrangement, and motions of
parts of matter. He was very conscious of not introducing more properties
than are required in order to construct viable explanations of natural phe-
nomena, and he suggested working with only three kinds of basic material
particle that are distinguished by their size, shape, and motion. These
were called ‘elements’.