R. Descartes, Principia Philosopiae,
Born at La Haye, in the French
province of Turenne, was educated at the Jesuit college of Le Flèche,
where he received a sound education in the classics and science. He
received his degree in Law at Poitiers, and in 1618 he enrolled in
the army of Maurice of Nassau, beginning a series of journeys which
took him to Holland (where he befriended Isaac Beeckman), Germany
and Bohemia. He returned to his homeland in 1622, and went often to
Paris, where he frequented Mersenne's coterie. In the Spring of 1629,
he left for Holland, where he stayed, living in various cities, until
1649. In October of that year, having been invited to teach philosophy
by Queen Christina, he went to Sweden. His stay there lasted only
a few months: after a brief illness, Descartes died in February, 1650,
Descartes is one of the main figures in
Western philosophical and scientific culture. The inventor of a system
of thought which marked out an epoch, he initiated a new movement
in philosophy. He was also, at the same time, a mathematician of genius,
to whom we owe the creation of a crucial branch of modern mathematics:
Cartesian physics also plays a fundamental
role in the history of science, enjoying a wide diffusion and reputation
throughout Europe. Based on a strictly mechanistic system, in which
phenomena are explained purely in terms of matter and local movement,
the cartesian vision had the rejection of the void as one of its bases.
in fact claimed that the fundamental attribute of matter was extension.
No physical being could exist if it did not occupy space; therefore
everything that materially exists has a spacial dimension - it is
"extended substance". In this sense, the void, that is, an "empty
space", is absolutely impossible: given the identification of extension
and matter, there can be no part of space in nature devoid of matter.
Those parts of space which seem to be "empty" are, in fact, "full",
even if they are full of different matter than ordinary space, more
rarified and imperceptible, what Descartes called "subtle matter".
According to Descartes, it is just such "subtle matter" that we mistakenly
call the "vacuum".