PHL100Y1 : Study Guide for Descartes
Document Summary
He realises most of his knowledge (esp. for science) is unreliable, and the only way is to rebuild it from the foundations: systematic doubt (95) He proposes to destroy all his opinions, and only accept as knowledge those which are totally certain, rejecting the rest. Opinions should be rejected if there is any way in which they could be false: mistrusting the senses (96) The senses are instantly rejected, because they are obviously occasionally deceptive, and they certainty can"t be proved: madness and dreams (96-7) The idea that daily experience is all wrong seems mad, but then he realises that dreams are a sort of daily madness, and he believe them. There is no clear proof that he is not currently dreaming: reality remixed (97) Although he may be dreaming, perhaps he can deduce what reality is like - it is the components out of which dreams are made.