• He was one of the most important thinkers of the early modern period.
• His work in philosophy and mathematics set the tone for subsequent investigation of
• He looks at radical skepticism (when everything we believe has doubt).
• Descartes wrote six meditations.
Meditation 1 (what can be called into doubt):
• When he was a child, he felt that he had been deceived, and was stuck by a large number
of falsehoods that he believed (example) Santa Claus.
• He wanted to forget everything completely and start again with foundations so that
anything he learned in the sciences and generally would be stable and likely to last.
! His beliefs had to be foundational. They provide foundations of security. Overall, beliefs
have strong and secure foundations.
- Skepticism: This is anyone who challenges our beliefs.
- Reasons to doubt: If you can find a reason to doubt your beliefs and see something
false about it, then you should reject it.
• He wants to know how we know when something we know is right or wrong.
! If the belief isn’t certain and have “reasons to doubt” then you should reject your belief.
! It doesn’t have to be everything that you question, but the basic principles that all your
beliefs rested on.
• Reasons to doubt 1
- He believes that people’s beliefs came from their senses.
! He believes that the senses deceive, and we should never completely trust those who
have deceived us even once.
• Reasons to doubt 2
- He considered himself a madman.
! But then he realized that madmen have some sort of brain damage/disorder.
! People with mental illnesses can be deceived depending on what their mind are telling
• Reasons to doubt 3
- People who sleep can dream about the same experience while asleep while madmen
do when awake.
! Sleeping is deceiving because when you are dreaming you are in a “fake world”.
! Sometimes people actually believe in their dreams, although they are false.
! Some of these people are convinced that their dreams are real when that cannot be the