Overview
How do you know you aren’t dreaming right now? How do you know the world wasn’t created 5 minutes ago with false memories implanted in your head? Skepticism is the annoying friend who asks “But are you sure?”
Core Idea
Cartesian Skepticism: Descartes tried to doubt everything to find one thing he couldn’t doubt. He found “Cogito, ergo sum” (I think, therefore I am). Everything else (the external world, your body) could be an illusion.
Formal Definition (if applicable)
Brain in a Vat: A thought experiment. If a mad scientist put your brain in a jar and stimulated it with electrodes to simulate reality, you wouldn’t know the difference. Therefore, you can’t know you aren’t a brain in a vat.
Intuition
Skepticism isn’t about denying reality; it’s about denying knowledge of reality. A skeptic looks both ways before crossing the street, but admits they can’t prove the car is real.
Examples
- Pyrrhonian Skepticism: Suspending judgment on everything to achieve peace of mind (ataraxia).
- Academic Skepticism: “I know that I know nothing” (Socrates).
- Global Skepticism: Doubting everything.
- Local Skepticism: Doubting specific things (e.g., moral skepticism, religious skepticism).
Common Misconceptions
- “Skeptics don’t believe in anything.” (They just withhold assent.)
- “It’s useless.” (It forces us to sharpen our arguments and define what knowledge really is.)
Related Concepts
- Solipsism: The view that only your own mind exists.
- Fallibilism: We can know things, but we can never be 100% certain.
- Matrix Hypothesis: Modern version of the Brain in a Vat.
Applications
- Science: Organized skepticism is a core value. Always question the data.
- Critical Thinking: Don’t believe everything you read.
Criticism / Limitations
“Here is a hand.” (G.E. Moore’s common sense refutation). If skepticism leads to absurd conclusions, maybe the premises are wrong.
Further Reading
- Descartes, Meditations on First Philosophy
- Sextus Empiricus, Outlines of Pyrrhonism