DESCARTES
THE RATIONALIST
Method
INTROSPECTION
Descartes' first published work was a scientific treatise. However, he prefaced this with a "Discourse on Method", which is his first philosophical work and indicates a new approach to philosophy. He starts by abandoning the opinions and beliefs of others, no matter how learned they may claim to be. "The Discourse" is even written in French, not the Latin of the philosophers. It is aimed at the ordinary upright person who may not have read too many books but had good sense. He wishes to be judged by natural reason rather than by comparison with learned books He will seek no science other than "what might be found in himself or in the great book of the world". His methodology is both subjective and introspective.
METHOD OF DOUBT
"I resolved to pretend that everything that had ever entered my mind was as false as the figments of my dreams. But then, immediately as I strove to think of everything as false, I realized that in the very act of thinking everything false, I was aware of myself as something real; and observing that the truth: I think, therefore I am, was so firm and so assured that the most extravagant arguments of the sceptics were incapable of shaking it, I concluded that I might have no scruple in taking it as the first principle of philosophy for which I was looking."
(Meditation 1)
Descartes adopted a method of systematic doubt. Nothing was to be trusted, certainly not the senses and perceptions. With the light of his reasoning he systematically cuts a swathe through his forest of doubts until but one tree still stands. This tree of indisputable knowledge has but one branch and it reads "I exist". The single branch is supported by a trunk which reads: "I think". I cannot be deceived if I do not exist. By the very act of doubting, I am thinking. By the very act of thinking, I confirm my existence. "I exist" cannot but be true when thought of ; but it has to be thought of to be doubted.