8: Doubt and Knowledge



Key Terms

Innate knowledge
Cogito Ergo Sum
Wax Argument

  • Read and analyze a description of philosophical thought
  • Articulate key conceptual distinctions between modern views of reality
  • Articulate key conceptual distinctions between rationalism and empiricism
  • Demonstrate knowledge of Cartesian Doubt, the Wax Argument for Rationalism.

I. The Pursuit of Knowledge

  • A. Leaving the Dark Ages
    • Authority in the Medieval World: Church
    • Change initiated by Protestant Reformation, Scientific Revolution, Rise of Universities, Printing Press
    • Rediscovery of Classical Philosophy
  • B. Types of Knowledge
    • Epistemology - how we make truth-claims
    • What is knowledge and how is it acquired?
    • Can we know?
      • No - Skepticism
      • Yes - How do we know?
  • C. Rationalism and Empiricism
    • Rationalism = a priori = reason
    • Empiricism = a posterior = senses

Descartes’s Doubt


But what, then, am I? A thinking thing, it has been said. But what is a thinking thing? It is a thing that doubts, understands, [conceives], affirms, denies, wills, refuses; that imagines also, and perceives.

II. Cartesian Doubt

  • A. Methodological Skepticism
    • What does it mean to be certain?
    • Certainty means inability to doubt
    • So subject all beliefs to doubt to find the foundation that is undoubtable
  • B. Method of Doubt
  • C. The Undoubtable Foundation
    • Cogito Ergo Sum = I think, therefore I am
    • This is clear and distinct, or undoubtable
  • D. Wax Argument for Rationalism
    • Observing the difference between wax at room temperature and heated wax
    • Reason tells us that room temperature and heated wax are the same though physical properties are different

III. Descartes on the Self

  • A. How do we know about the self? 
    • Doubt
    • Cogito ergo sum = I think therefore I am
    • Thought is “what happens in me such that I am immediately conscious of it”
  • B. What is the nature of the self?
    • Dualistic - material body, immaterial soul
    • The mind and the brain/body are two separate things
    • The mind is a non-physical thinking thing
    • The brain/body is a physical non-thinking thing
    • Scientific dissection tells scientists that the brain is a mechanical thing
    • The mind operates the brain and the brain operates the body

Also See: What is Modernity?

Logic Week 8: False Dilemma and Straw Man