AS Philosophy - Descartes' a Priori Reasoning

AS Philosophy - Descartes' a Priori Reasoning

1. POINT 1

   • All sensory experiences can be doubted. Sensory (empirical) evidence is doubtable.
     • - all sense experience is produced by an 'evil demon'
     • - you cannot tell that the experience is false by experience
     • EMPIRICISM FAILS TO SECURE CERTAINTY
       • - cannot know whether or not the experience is true or false because we cannot doubt the origins of our sense experience

2. POINT 2

   • Something that cannot be doubted. "I think therefore I am"
     • Descartes' realises that when he is thinking, he exists, even if an evil demon is trying to convince him that he isn't
     • Descarts cannot doubt that he is thinking
     • Descartes arrives at his certainty through reasoning and intuition

3. POINT 3

   • Descartes cannot doubt that he exists but he can doubt that he is physical
     • - Descartes only believes he has a body because of sense experiences, but these are doubtable (evil demon)

4. POINT 4

   • Descartes offers 3 options for what might cause our experiences of physical objects
     • 1. Real world
     • 2. God
       • God is the creator of (false) experiences of physical objects because he would be decieving us.
     • 3. Evil demon
       • God is no deciever because he's not a demon - because God would be allowing a demon to convince us of something false, but god isn't a deciever
     • CONCLUSION 1
       • Because god is perfect, he is not a deciever, so if god exists there must be an external physical world
     • CONCLUSION 2
       • There must be a self + physical world because both can be justified through rational intuition and demonstration. As long as god exists, sense experience cannot reach this proof, because it is doubtable.