Overview

Epistemology is the study of knowledge. It asks: What do we know? How do we know it? And how can we be sure we aren’t wrong?

Core Idea

The core idea is justification. It’s not enough to believe something true (you could be lucky). To have knowledge, you need a good reason (justification) for your belief.

Formal Definition

Classically defined as Justified True Belief (JTB). $S$ knows that $P$ if and only if:

  1. $P$ is true.
  2. $S$ believes that $P$.
  3. $S$ is justified in believing that $P$.

Intuition

It’s the audit of the mind.

  • “I know it’s raining.” (How? I see water falling).
  • “I know God exists.” (How? Faith? Logic? Experience?).
  • “I know $E=mc^2$.” (How? I trust Einstein).

Examples

  • Rationalism: We know things through reason alone (Descartes: “I think, therefore I am”).
  • Empiricism: We know things through sensory experience (Hume: “All knowledge comes from impressions”).
  • Skepticism: We can’t really know anything (The Matrix scenario).

Common Misconceptions

  • Misconception: Knowledge is just strong belief.
    • Correction: You can strongly believe the earth is flat, but you can’t know it (because it’s false).
  • Misconception: Science is the only way to know things.
    • Correction: That is “Scientism.” We also know logical truths ($A=A$) and ethical truths (Torture is wrong) without using the scientific method.

Applications

  • Law: Evidence and “Reasonable Doubt” are epistemological standards.
  • AI: Machine Learning is essentially computational epistemology (learning from data).

Criticism and Limitations

  • Regress Problem: If every belief needs a reason, and that reason needs a reason… do we go on forever (Infinitism), go in a circle (Coherentism), or stop at a bedrock foundation (Foundationalism)?

Further Reading

  • Epistemology: A Contemporary Introduction by Robert Audi
  • The Problems of Philosophy by Bertrand Russell