Philosophy of Knowledge: Arguments, Skepticism, and Induction

Valid Argument

If the premises are true, the conclusion must follow.

Sound Argument

It's valid and its premises are true.

Deductive Argument

An argument that guarantees the conclusion if valid.

Inductive Argument

An argument that makes the conclusion probable, not certain.

Conceptual Analysis

Clarify the meaning of a concept.

Counterexample

By showing a case that fits the definition but contradicts intuition (e.g., Gettier cases).

Thought Experiment

An imaginary case used to test concepts.

Descartes's Distrust of Senses

They sometimes deceive us, so they can't provide certainty.

Dream Argument

We can't know if we are awake or dreaming.

Evil Demon Hypothesis

A powerful deceiver could make us wrong even about math/logic.

Austin's Objection to Descartes

Descartes misuses 'know,' setting standards too high compared to ordinary usage.

Stroud's Response to Austin

Even in ordinary contexts, we can't rule out skeptical possibilities.

Skeptical Hypothesis

Casts doubt on knowledge.

Metaphysical Hypothesis

Explains what reality is made of.

Chalmers's Physics Analogy

Physics says reality = particles/fields; Matrix says reality = computer code.

Neo's Hair Objection

Neo falsely believes he has biological hair.

Chalmers's Reply to Neo's Hair

Neo really does have virtual hair in the Matrix, so his belief isn't false.

Recent Matrix Hypothesis

A simulation layered on top of our real world.

Experience Machine Thought Experiment

That we value authenticity, truth, and reality beyond just pleasure.

Hume's Problem of Induction

We have no justification for believing the future will resemble the past.

Circularity Worry

Using induction to justify induction is circular reasoning.

Responses to Hume's Problem

Laws of nature (assume regularity), Probability (expectation, not certainty), Pragmatic (induction works in practice).

Goodman's Grue Problem

'All emeralds are green' vs. 'All emeralds are grue' (green before 2100, blue after).

Grue Problem Implication

Induction depends on which concepts are natural/projectible.