Descartes: A Biography

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 Descartes: A Biography

At the same time, Descartes adopts a metaphysical background that

attributes all these laws to nature, where the term ‘nature’ does not

mean ‘some goddess or any other kind of imaginary power, but...matter

itself...oncondition that God continues to conserve it in the same way

as He created it’ (xi.). Once God’s activity is accepted as unchange-

able, Descartes can avoid ‘getting further involved in these metaphysical

questions’ (xi.). There is a clear distinction, then, between God as the

ultimate cause of matter and motion, and the contingent events in the

world that are the proximate causes of natural phenomena. ‘One must say

that God alone is the author of all the motions that occur in the world, in so

farasthey exist and in so far as they are rectilinear, but that it is the various

dispositions of matter that make them irregular and curved’ (xi.). The

simplicity and immutability of the actions attributed ‘by theologians’ to

God mean that God’s agency can be omitted from a scientific account of

natural phenomena, because the focus of attention is on those changeable

conditions that explain differences between phenomena rather than on

the general background that they all share in common.

With that distinction in place, Descartes speculates about the disposi-

tions of matter in motion that would be required to explain such natural

phenomena as the Sun and the stars, the motion of the planets and of

comets, the weight of bodies, the tides, the nature and properties of light,

and how the heavens would appear to inhabitants of the Earth. He cautions

the reader that he will not provide ‘exact demonstrations of everything

that I say’ (xi.) about such a wide range of phenomena, since that

would diminish the pleasure of discovering them for oneself. He reverts,

instead, to the notion of constructing a fable. Readers may then accept

or reject his hypotheses by considering the progress made in explanation

and the plausibility of alternatives. ‘Thus I shall be content to continue

the description that I have begun, as if my only plan were to tell you a

fable’ (xi.).

The fabulous character of the resulting discourse could not camouflage

the fact that its author was clearly endorsing the same heliocentric system

that had been proposed by Copernicus and Galileo. The whole structure

of Cartesian cosmology depended on assuming an indefinitely extended

space, in which there are indefinitely many suns or fixed stars, each of which

is surrounded by whirling vortices. Each vortex includes masses of matter,

or planets, that spin on their own axes and move in a circular motion around

a central sun. ChapterofThe Worldthus unambiguously described the