Meditations on First Philosophy

  • Originally published in 1641
  • Masked his true intention with notes about the existence of God
    • Primary goal: epistemological (epistemology)
      • Discover their abilities in knowledge/belief
      • Epistemology --> "First Philosophy"
      • Before we can answer questions about "what is", we must answer questions about "what we can know"
    • Secondary goal: metaphysical (metaphysics)
      • Use their discovered cognitive abilities
  • Cartesian Skepticism
  • Deals with the existence of God and the distinction between the human soul and body

Meditation I

  • Goal is to show us that the senses do not provide certainty
    • Belief in them needs to be argued for
  • Stages of Doubt
    1. Doubts arising from the senses
      • Deductive argument
      • The argument
        • Premise 1: Our senses have deceived us in the past
        • Premise 2: It is unwise to trust completely those who have deceived us even once
        • Conclusion: One should not place absolute confidence in one's senses
      • Premise 2 could be rejected in that it only applies to specific cases
        • Observing things far away, tiny things, things in bad light, etc.
    2. The dream hypothesis
      • The argument
        • Premise 1: You can never be completely certain that you are not dreaming
        • Premise 2: You can only be completely certain that your perceptions are accurate if you can be sure you aren't dreaming
        • Conclusion: You can never be completely sure your perceptions are accurate
    3. Imperfect God hypothesis
      • An all-powerful God could manipulate math, etc.
    4. Evil demon hypothesis
      • All-powerful, evil demon doing everything possible to deceive you

Meditation II

  • The argument
    • I think, therefore I exist
      • I think, therefore I am
      • First person proposition
      • Psychological component
    • If I'm thinking, there must be a "me" to do the thinking
    • What is the I that thinks?
      • Something aware of its own consciousness

Philosophy Rene Descartes