decartes

• most influential philosopher of the 18th century
• made Cartesian coordinates
• the dominant philosophical view at the time
• Aristotle was the dominant philosophical view
• sextus empiricus - is a skeptic : greek philosophical school  
• Aristotle is an empiricist : someone who thinks all of our knowledge comes from experience in particular all our concepts
• rationalism ( associated with plato) - sophisticated decartes
• concepts are innate
• empiricists (Aristotle) - scholastics , all understanding comes from experience
• if I can find reason to doubt I will doubt it
• metaphysical skepticism and ordinary scepticism
•  it may undermine an empiricist
• shouldn't doubt your senses even if you make mistakes
• melancholy- the disease of having black bile in your system causing hallucinations
• ordinary deceptive sensations 
• all other sensations are safe  ( dream argument) - all bodies are lost = what's left is colors extension., numbers, motion, time, place, shape, no physics or medicine or astronomy but mathematics exists
• start with all sensations
• if god is good why did he make me be able to be deceived
• not god - evil genius
• if there is an evil demon he can trick me  - I can be completely deceived - filtered out, colors extensions mathematics, etc. 
• My having of sensations can't be unreal