Descartes and Newton: Competing Theories of Scientific Knowledge 299Any person, Descartes claimed,
has to begin as a blank slate in order
to understand the world through
deductive reasoning. “I think, there
fore I am” (CogitOy ergo sum) was his
starting point, the postulation of a
self-evident truth and the assertion
that the ability to think is the basis of
human existence. Then each problem
has to be separated, he argued, into
‘‘as many parts as may be necessary
for its adequate solution,” moving
from the simplest idea to the most
difficult, in the same way as a mathe
matical proof is formulated. Carte
sianism (the philosophy of Descartes
and his followers) held that the world ^en<^ Descartes,
could be reduced to two substances:
mind and matter, ‘‘thinking substance” and “extended substance.” Matter—
defined as an infinite number of particles that fill all space, leaving neither
void nor vacuum—could be discovered and described mathematically, as
could the laws of motion. Beginning with the certainty of his own existence,
Descartes argued that the existence of the material universe and God could
be deduced. ‘‘Begin with the smallest object, the easiest to understand,” he
insisted, ‘‘and gradually move to a knowledge of those that are the most
complex.”
This materialist approach to knowledge left little or no room for ancient
or medieval learning. As a sign of this break, Descartes published his works
in French, identifying Latin with scholasticism and ecclesiastical doctrine.
Like Kepler, Descartes viewed God as a benevolent, infinitely powerful
clockmaker, who created the universe according to rules that the human
mind could discover with proper reasoning. God then stepped back, accord
ing to this view, forever absent from the actual workings of what He had
created.
Mathematics, Descartes argued, demonstrates ‘‘the certainty and self
evidence of its reasonings.” It therefore stood as the foundation of all sci
ence. Eventually a rule for every phenomenon could be discovered. Descartes
thus subordinated experimentation to reason in the quest for truth. One of
the stream of savants who went to meet Descartes recalled that ‘‘many of
them would desire him to shew them his Instruments ... he would drawe
out a little Drawer under his Table, and shew them a paire of Compasses
with one of the Legges broken; and then, for his Ruler, he used a sheet of
paper folded double.”