Descartes's Meditations I and II

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Background on Descartes

• Lived 1596-1650
• Accomplished mathematician, devoted to the development of science, but appears also to have eagerly wanted to reconcile science with the Christian beliefs of his time
• Schools were dominated by a set of views called "scholasticism," which was a combination of Aristotle and Church doctrines
• Descartes aims to reject scholasticism with a radical new start to human knowledge (rejection of Aristotleanism and scholasticism was a key feature of the leading scientific thinking, such as in Galileo). The Meditations are his most compelling attempt to develop this new foundation
• Note: these meditations are Descartes alone! Knowledge is not for him being led by a teaching but rather by reasoning.

Meditation I

• Descartes decides to begin by withholding belief in opinions which are not certain. This can be done through systematic doubting - by attacking his most fundamental opinions.
• He has always assumed that sense were his primary source of knowledge, BUT
  • Mad people see things that aren't there
  • Dreams seem real when we have them
  (Note that in dreams and imagination we compound things to make new things - this suggests that compound beliefs are more dubious than simple ones.
• But cannot one assume God exists? Descartes piously says that we can, but agrees to set this issue aside.
• A thought experiment: assumer there is an evil demon or power that generates a complete deception occurring all around me, and for all of my senses, for the duration of my life. Now, is anything certain?

Meditation II

• Descartes begins by doubting everything, and asking what remains (what cannot be doubted)
• "Cogito ergo sum"
• What is the thing that thinks?
  • Not a "rational animal" (scholasticism's definition)
  • Not a body that walks, eats, etc.
  • Not a sensing thing
  • BUT: a thinking thing. I exist as long as I am thinking.
• Imagination cannot tell me what I am
• Doubt, understanding, affirmation and denial, will, refusing, imagination are all features of thought that cannot be without me
• How do we then understand bodies? Primarily through reason. Example: I know that infinite variations in form are possible for wax, but these cannot be perceived or imagined
• Reason grasps the true nature of wax
• Perception is mental inspection
• Truth is known when we understand clearly and distinctly
• Judgment leaps beyond what is given in perception