Introduction to Skepticism

Skepticism

The theory that certain knowledge is impossible

Local Skepticism

Skepticism confined to some set of propositions, bits of supposed knowledge, or beliefs

Radical Skepticism

Skepticism that is “thoroughgoing” and applies broadly to many things

Skepticism about X

We do not know anything about X

Skepticism about Other Minds

We do not know anything about what other people think or feel

Skepticism about the Future

We do not know anything about what will happen in the future

Skepticism about the Past

We do not know anything about what happened in the past

Inductive Skepticism

We do not know any general facts, because we do not know the propositions that result from induction

External World Skepticism

We do not know anything about the world outside of our minds

Pyrrhonian Skepticism

We should suspend our belief in everything

Academic Skepticism

We do not know anything at all, and knowledge is impossible

Belief

A mental state of accepting a proposition as true, regardless of its actual truth value

Knowledge

A belief that is not only true but also supported by evidence or reasoning

Epoché

The suspension of judgment

Ataraxia

A state of serene calmness

∴

Symbol meaning “therefore”

Modus Tollens

• Denying the consequent

• If P, then Q. ¬ Q ∴ ¬ P

¬

Symbol meaning “not” or “it is not the case that”

Closure Principle

If you know that P, and P deductively entails Q, then you are in a position to know that Q

The Possibility of Pervasive Error

The philosophical idea that error is so widespread and ingrained in our cognitive processes that it fundamentally undermines our ability to confidently claim knowledge about anything