Lecture Notes: Skepticism in Epistemology

Introduction to Epistemology

• Speaker: Daniel Greco, Assistant Professor of Philosophy at Yale University
• Topic: Epistemology - the study of knowledge

Skepticism

• Definition: The idea that we know much less than we believe we do.
• Focus: Skepticism regarding knowledge of the unobserved.

David Hume's Skepticism

• Who: David Hume, 18th-century Scottish philosopher and historian.
• Target: Our knowledge of things that we haven't directly observed.

Examples of Knowledge of the Unobserved

• Beliefs about unobserved facts:
  • Blue whales as the largest animals on Earth.
  • Alpha Centauri as the nearest star system.
  • Existence and conquests of Napoleon.
  • Date of the next American presidential election.

Relations of Ideas vs. Matters of Fact

Relations of Ideas

• Definition: Claims whose denial is inconceivable or self-contradictory.
• Examples:
  • All triangles have three sides.
  • Two apples plus two oranges equals four pieces of fruit.
• Characteristics:
  • Necessary truths, true regardless of how the world turns out.
  • Knowable through the mere operation of thought.
  • Discoverable without any dependence on external existence.

Matters of Fact

• Definition: Claims whose denial is conceivable and not contradictory.
• Examples:
  • It is rainy outside.
  • The speaker owns a fluffy puppy.
• Characteristics:
  • Their truth requires observation and evidence.
  • Denials of these claims are conceivable.

Comparison of Relations of Ideas and Matters of Fact

• Relations of Ideas:
  • Known a priori (independent of experience)
• Matters of Fact:
  • Known a posteriori (dependent on experience)

Connection to Kant

• Immanuel Kant: Explored the distinction between a priori and a posteriori knowledge.

Summary

• Hume’s skepticism challenges our assumptions about knowledge of the unobserved.
• Distinction between necessary truths (relations of ideas) and contingent truths (matters of fact).