By kind
Thought experiments
A scenario built to isolate one intuition and test it.
15 entries
Mary's Room
A scientist who knows every physical fact about color but has only seen black and white: when she first sees red, does she learn something new, and if so, is physicalism false?
10 min
Thought experimentThe Brain in a Vat
How could you tell, from the inside, that you are not a disembodied brain in a tank being fed a lifelike stream of fake experience?
8 min
Thought experimentThe Chinese Room
A man who processes Chinese by rulebook without understanding a word shows that running the right program is not the same as understanding.
9 min
Thought experimentThe Drowning Child
If you would ruin your suit to save a child drowning in front of you, why does a child dying far away have a weaker claim on you?
8 min
Thought experimentThe Euthyphro Dilemma
Is the good good because God commands it, or does God command it because it is good? Either answer costs the believer something.
8 min
Thought experimentThe Experience Machine
Nozick's machine offers a lifetime of perfect experiences; most people refuse it, which suggests we want more from life than how it feels from the inside.
8 min
Thought experimentThe Gettier Problem
A short 1963 paper showed that a belief can be true, and justified, and still not count as knowledge, breaking a definition that had stood since Plato.
9 min
Thought experimentThe Mere Addition Paradox
Parfit's step-by-step trap: adding happy people is not bad, and equalizing while raising welfare is good, yet repeating these steps proves a huge population of barely worthwhile lives is best.
8 min
Thought experimentThe Prisoner's Dilemma
Two rational actors, each acting in their own interest, reach an outcome that is worse for both than if they had cooperated.
9 min
Thought experimentThe Repugnant Conclusion
If total welfare is what matters, an enormous population of lives barely worth living beats a small population of wonderful ones, and Parfit found every escape route blocked.
9 min
Thought experimentThe Ship of Theseus
If every plank of a ship is replaced one by one, is it still the same ship? A puzzle about what makes a thing the same thing over time.
8 min
Thought experimentThe Ticking Time Bomb
A hypothetical bomb, a captured terrorist, and a clock: the scenario built to make torture look not only permissible but obligatory.
8 min
Thought experimentThe Trolley Problem
A pair of near-identical dilemmas designed so that our intuitions diverge, forcing us to say what actually makes killing wrong.
10 min
Thought experimentThe Veil of Ignorance
A device for finding just rules: choose the principles of your society without knowing who in it you will be.
9 min
Thought experimentWhat Is It Like to Be a Bat?
There is something it is like to be a conscious creature, and Thomas Nagel argues that this inside view is exactly what a purely physical description of the brain can never capture.
9 min