Lecture 23 Notes

Introduction to Epistemology

1. In epistemology, we explore our access to the truth; examine human reason, perception, and knowledge.
2. We will study three greater philosophers and their different epistemologies: Descartes, Locke, and Berkeley.

Descartes' Project: Background

1. Descartes (1596-1650)
   
1. "Father" of Modern Philosophy; Multi-talented Genius
2. A Deeply Committed Catholic
2. The Goal: An Edifice of Knowledge
1. Descartes builds an inverted pyramid.
2. The foundation of the pyramid is what he believes he knows with certainty.  Upon this certain belief, he will try to build the rest of his knowledge.
3. The Ground Rules: Avoid Error
1. Descartes attempts to avoid error by basing his beliefs ultimately on things that he knows with certainty.
2. Certainty and Justification
• Chains of Justification--Descartes will try to build chains of justification between his beliefs.
  
• Need for Certainty in First Link--In order to avoid error, the first link in the chain of justification must be known with certainty.

Seeking The Foundation

1. Method
1. Goal: Seeking a Solid Foundation For the Inverted Pyramid of Knowledge
2. Requirement: Absolute Certainty
3. Primary Tool: The Wrecking Ball of Cartesian Doubt
• Cartesian vs. Ordinary Doubt--In Cartesian Doubt, we are to doubt anything that could possibly be false.  In Ordinary Doubt, we doubt anything that is probably false.
• Descartes uses this high standard for doubt as a wrecking ball on his previous edifice of knowledge.  Any belief that he once held that could possibly be false will be doubted. 
4. Labor Saving Device: Grouping Beliefs By Virtue of Their Type of Support.
• Instead of considering each belief individually, Descartes will question sources of beliefs.
• For example, he will group together beliefs that are formed on the basis of the senses.
2. Three Assaults on Previous Knowledge
1. First Assault on the Senses: The Argument from Illusion
• The Argument--Some of our sensory beliefs turn out to be illusions.  For example, at a distance a dry road may appear wet.  Therefore, we should doubt all of our beliefs that are based on the senses.
  
• Reply--Senses seem to work okay much of the time.
2. Second Assault on the Senses: The Dreaming Argument
• The Argument--We can't be certain that we aren't now dreaming.  So the beliefs we form on the basis of the senses could possibly be false.  Therefore, we should doubt all of our beliefs that are based on the senses.
3. Third Assault on the Senses; Primary Assault on A Priori (Mathematical) Beliefs and (Almost) Everything Else: The Deceiving Demon Argument
• The Argument--It is possible that whenever I form a belief from any source (a priori, the senses, etc) I am really being deceived by a demon.
• This argument clears the decks with doubt.  No source is immune from the deception of the demon.
• Note: Don't Need To Believe Demon is Real; Only Possible
  
3. The Foundation: The "Cogito"
   
1. "Cogito" = "I exist"
   
2. The Cogito is necessarily true every time I think it.
3. Even to be deceived we must exist and have mental states.
4. In other works, Descartes identifies this foundational belief as "Cogito Ergo Sum" or "I think therefore I am".
5. Descartes suggests that we can have certainty about the contents of the mind.  We may not know if thoughts and experiences are accurate, but we can know that we are having such thoughts and experiences.
6. The "Cogito" is Descartes' Archimedian Point; he will try to rebuild his entire edifice of knowledge on the basis of it.

Engraving from Mechanics Magazine, London, 1824 (320px x 214px)