# Awesome Thought Experiments

![Awesome Thought Experiments banner](assets/banner.svg)

*Explore the questions that challenge reality, reason, morality, and human understanding.*

A curated, self-contained educational collection: original explanations, competing responses, reflection questions, scholarly references, and connected reading paths. Read it on GitHub or download it for offline study. External references require internet access; the original learning content does not.

**132 entries · 12 categories · 11 learning paths.** Each article identifies its type and sources. See the [quality report](QUALITY_REPORT.md) for checks and research limitations.

## What is a thought experiment?

A thought experiment asks you to reason through an imagined situation to examine a claim. The assumptions matter as much as the story. An intuition can motivate an argument without proving its conclusion.

This collection also includes explicitly labelled **paradoxes** (apparently conflicting claims or derivations), **puzzles** (problems with specified rules), **models** (simplified systems), and **arguments** or **analogies**. An empirical experiment instead gathers observations from the world. Some imagined scenarios later inspired laboratory work; those stages should not be conflated.

Difficulty measures prerequisites: **B** Beginner, **I** Intermediate, **A** Advanced. It does not measure the importance of the question or the difficulty of resolving it.

## Contents

- [Recommended starting points](#recommended-starting-points)
- [Guided learning paths](#guided-learning-paths)
- [Explore the collection](#explore-the-collection)
- [Connections](CONNECTIONS.md)
- [Sources and attribution](SOURCES_AND_ATTRIBUTION.md)
- [Contributing](CONTRIBUTING.md)
- [Getting started and local checks](GETTING_STARTED.md)
- [Quality report](QUALITY_REPORT.md)

## Recommended starting points

- [Ship of Theseus](experiments/identity/ship-of-theseus.md) — What makes something persist?
- [Trolley Problem](experiments/ethics/trolley.md) — What counts as an acceptable sacrifice?
- [Mary’s Room: The Knowledge Argument](experiments/consciousness/marys-room.md) — Can a complete description leave something out?
- [Chinese Room](experiments/consciousness/chinese-room.md) — Does following rules amount to understanding?
- [The Monty Hall Problem](experiments/mathematics/monty-hall.md) — How does information change probability?

## Guided learning paths

- [Start Here: 10 Thought Experiments for Beginners](learning-paths/start-here.md)
- [Understanding Consciousness and Identity](learning-paths/consciousness-and-identity.md)
- [Ethics and Difficult Moral Decisions](learning-paths/ethics-and-decisions.md)
- [Reality, Knowledge, and Skepticism](learning-paths/knowledge-and-skepticism.md)
- [Paradoxes, Probability, and Rational Choice](learning-paths/paradoxes-and-choice.md)
- [The Universe, Time, and Physical Reality](learning-paths/universe-time-and-reality.md)
- [Artificial Intelligence and the Future of Intelligence](learning-paths/ai-and-intelligence.md)
- [Language, Meaning, and Self-Reference](learning-paths/language-meaning-and-self-reference.md)
- [Science, Evidence, and Explanation](learning-paths/science-evidence-and-explanation.md)
- [Time, Fate, and Freedom](learning-paths/time-fate-and-freedom.md)
- [Cooperation, Choice, and Collective Decisions](learning-paths/cooperation-choice-and-collective-decisions.md)

Each path includes objectives, an ordered reading sequence, reflection questions, and a final independent synthesis activity. No ChatGPT account or learning platform is needed.

## Explore the collection

| Category | Entries |
| --- | ---: |
| [Ethics and Moral Philosophy](#ethics-and-moral-philosophy) | 14 |
| [Identity and Personal Existence](#identity-and-personal-existence) | 11 |
| [Consciousness and Philosophy of Mind](#consciousness-and-philosophy-of-mind) | 13 |
| [Reality, Knowledge, and Skepticism](#reality-knowledge-and-skepticism) | 17 |
| [Logic, Language, and Paradoxes](#logic-language-and-paradoxes) | 13 |
| [Time, Causality, and Free Will](#time-causality-and-free-will) | 11 |
| [Physics and the Universe](#physics-and-the-universe) | 14 |
| [Mathematics and Probability](#mathematics-and-probability) | 9 |
| [Economics and Decision Theory](#economics-and-decision-theory) | 8 |
| [Artificial Intelligence and Machine Ethics](#artificial-intelligence-and-machine-ethics) | 8 |
| [Society, Justice, and Political Philosophy](#society-justice-and-political-philosophy) | 9 |
| [Science, Biology, and Evolution](#science-biology-and-evolution) | 5 |

### Ethics and Moral Philosophy

- **B** [Drowning Child](experiments/ethics/drowning-child.md) — How far does an easy duty of rescue extend beyond people immediately in front of us? *Type: thought experiment.*
- **B** [Experience Machine](experiments/ethics/experience-machine.md) — Is the quality of experience all that makes a life good for its subject? *Type: thought experiment.*
- **I** [Jim and the Captain (the Integrity Objection)](experiments/ethics/jim-and-the-captain.md) — Do a person’s deepest commitments and sense of integrity count for something in deciding what to do, or must they be weighed like any other preference in an impartial calculation? *Type: thought experiment.*
- **A** [Nonidentity Problem](experiments/ethics/nonidentity-problem.md) — Can a choice be wrong even if it makes no particular person worse off than that person otherwise would have been? *Type: thought experiment.*
- **A** [Repugnant Conclusion](experiments/ethics/repugnant-conclusion.md) — Can enough minimally good lives make a world better than one containing fewer excellent lives? *Type: argument.*
- **B** [Smith and Jones: Killing and Letting Die](experiments/ethics/smith-and-jones-bathtub.md) — Is there a moral difference between doing harm and allowing harm when everything else is held equal? *Type: thought experiment.*
- **I** [Survival Lottery](experiments/ethics/organ-lottery.md) — Can an impartial procedure make compulsory lethal sacrifice morally acceptable? *Type: thought experiment.*
- **B** [The Euthyphro Dilemma](experiments/ethics/euthyphro-dilemma.md) — Does a moral standard depend on the will of a divine being, or does it hold independently of any will, including God’s? *Type: argument.*
- **I** [The Terror Bomber and the Tactical Bomber](experiments/ethics/terror-and-tactical-bomber.md) — Does it matter morally whether harm is intended as a means or merely foreseen as a side effect, when the outcomes are otherwise the same? *Type: thought experiment.*
- **I** [The Violinist](experiments/ethics/violinist.md) — Does a right to life automatically include a right to another person’s bodily support? *Type: thought experiment.*
- **B** [Transplant Problem](experiments/ethics/transplant.md) — Why might killing one to save five be forbidden even when five lives would certainly be saved? *Type: thought experiment.*
- **B** [Trolley Problem](experiments/ethics/trolley.md) — When, if ever, may saving several lives justify foreseeably killing one? *Type: thought experiment.*
- **I** [Utility Monster](experiments/ethics/utility-monster.md) — Can maximizing total well-being justify extreme concentration on a single beneficiary? *Type: thought experiment.*
- **I** [Williams’s Lorry Driver and Moral Luck](experiments/ethics/lorry-driver.md) — Can what happens, partly by chance, change how an agent should be morally assessed or how the agent should feel about their own conduct? *Type: thought experiment.*

### Identity and Personal Existence

- **I** [Brain Transplant: Brown and Robinson](experiments/identity/brain-transplant.md) — Which person, if either, survives when brain and the rest of the body come apart? *Type: thought experiment.*
- **I** [Brave Officer](experiments/identity/brave-officer.md) — Can a relation that fails transitivity constitute identity, which is transitive? *Type: thought experiment.*
- **I** [Dion and Theon](experiments/identity/dion-and-theon.md) — When a part is removed, does the original object survive, and what has become of the object that was the remainder? *Type: puzzle.*
- **A** [Fission and Personal Identity](experiments/identity/fission.md) — Can one person survive as two people without being identical to both? *Type: thought experiment.*
- **B** [Heraclitus’s River](experiments/identity/heraclitus-river.md) — Can something remain the same thing while its constituents are continually replaced? *Type: argument.*
- **B** [Locke’s Prince and Cobbler](experiments/identity/lockes-prince-and-cobbler.md) — Does the person follow bodily continuity or continuity of consciousness? *Type: thought experiment.*
- **I** [Lumpl and Goliath: The Statue and the Clay](experiments/identity/statue-and-clay.md) — Can two things be made of exactly the same matter at the same time, or must the statue and the clay be one and the same thing? *Type: puzzle.*
- **B** [Ship of Theseus](experiments/identity/ship-of-theseus.md) — What allows an object to remain the very same object while its parts change? *Type: thought experiment.*
- **A** [Swampman](experiments/identity/swampman.md) — Do a thinker’s meanings and thoughts depend partly on a history outside the thinker’s present physical state? *Type: thought experiment.*
- **I** [Teletransporter](experiments/identity/teletransporter.md) — Does perfect psychological reconstruction preserve you, or merely produce someone much like you? *Type: thought experiment.*
- **A** [The Problem of the Many (Tibbles the Cat)](experiments/identity/problem-of-the-many.md) — How can there be one cat when so many equally good candidate objects occupy nearly the same place? *Type: puzzle.*

### Consciousness and Philosophy of Mind

- **I** [Beetle in a Box](experiments/consciousness/beetle-in-box.md) — Can a wholly private object determine the meaning of a publicly used sensation word? *Type: thought experiment.*
- **A** [China Brain](experiments/consciousness/china-brain.md) — Can the right functional organization produce consciousness in an extremely unfamiliar physical implementation? *Type: thought experiment.*
- **B** [Chinese Room](experiments/consciousness/chinese-room.md) — Is executing a formally specified program sufficient for understanding? *Type: thought experiment.*
- **A** [Fading and Dancing Qualia](experiments/consciousness/fading-and-dancing-qualia.md) — Could experience change radically without any corresponding change in a system’s ability to notice? *Type: thought experiment.*
- **I** [Inverted Spectrum](experiments/consciousness/inverted-spectrum.md) — Could experiences differ while every relevant functional role remains the same? *Type: thought experiment.*
- **I** [Leibniz’s Mill](experiments/consciousness/philosophical-mill.md) — Can the interactions of extended parts explain a unified perception? *Type: thought experiment.*
- **I** [Mad Pain and Martian Pain](experiments/consciousness/mad-pain-martian-pain.md) — Can one theory of what pain is accommodate both a being whose pain plays an unusual causal role and a being whose pain has a different physical basis? *Type: thought experiment.*
- **I** [Mary’s Room: The Knowledge Argument](experiments/consciousness/marys-room.md) — If Mary learns something upon seeing red, does that show that physical knowledge leaves out facts about consciousness? *Type: thought experiment.*
- **A** [Philosophical Zombies](experiments/consciousness/zombies.md) — Is a physically identical world without consciousness genuinely possible? *Type: thought experiment.*
- **I** [Split Brains and the Unity of Consciousness](experiments/consciousness/brain-bisection.md) — How many minds, or streams of consciousness, are there in a patient whose brain has been divided? *Type: argument.*
- **B** [The Problem of Other Minds](experiments/consciousness/problem-of-other-minds.md) — How can anyone know that other beings have minds, and what could count as evidence for it? *Type: argument.*
- **I** [Twin Earth](experiments/consciousness/twin-earth.md) — Are the meanings of our words, and the contents of our thoughts, fixed entirely by what is in our heads, or do they depend on our environment? *Type: thought experiment.*
- **B** [What Is It Like to Be a Bat?](experiments/consciousness/bat.md) — Can an objective description fully capture an experience available only from a particular point of view? *Type: thought experiment.*

### Reality, Knowledge, and Skepticism

- **I** [Brain in a Vat](experiments/epistemology/brain-in-a-vat.md) — Could an entirely simulated sensory life undermine knowledge of the external world? *Type: thought experiment.*
- **B** [Descartes’s Evil Demon](experiments/epistemology/evil-demon.md) — A deliberately powerful deceiver tests which beliefs can survive radical doubt. *Type: thought experiment.*
- **I** [Descartes’s Piece of Wax](experiments/epistemology/wax-argument.md) — If every sensible quality of the wax can change while it remains the same wax, what is it that we know when we know the wax? *Type: thought experiment.*
- **I** [Fake-Barn Country](experiments/epistemology/fake-barn.md) — Accurate perception in a deceptive neighborhood tests whether a true belief is safe enough for knowledge. *Type: thought experiment.*
- **I** [Gettier Cases](experiments/epistemology/gettier-cases.md) — A belief can be justified and true while its truth appears to depend on the wrong kind of luck. *Type: thought experiment.*
- **I** [Goodman’s New Riddle of Induction (Grue)](experiments/epistemology/grue.md) — What distinguishes generalizations that our evidence legitimately supports from ones that fit the same evidence but should not be projected? *Type: paradox.*
- **I** [Hempel’s Paradox of the Ravens](experiments/epistemology/ravens-paradox.md) — Why does it seem wrong that a white shoe confirms a claim about ravens, and which assumption should we revise? *Type: paradox.*
- **I** [Hume’s Missing Shade of Blue](experiments/epistemology/humes-missing-shade-of-blue.md) — Can we form a genuinely new simple idea without a matching experience, and what would that show about empiricism? *Type: thought experiment.*
- **I** [Molyneux’s Problem](experiments/epistemology/molyneux-problem.md) — Could someone newly able to see recognize by sight shapes previously known only through touch? *Type: thought experiment.*
- **I** [Moore’s “Here Is One Hand”](experiments/epistemology/moores-proof-of-an-external-world.md) — Can a simple, obvious claim such as “here is a hand” be more certain than the philosophical premises used to doubt it? *Type: argument.*
- **I** [Norman the Clairvoyant](experiments/epistemology/norman-the-clairvoyant.md) — Is a belief justified or known if it is produced by a reliable process the believer has no access to or reason to trust? *Type: thought experiment.*
- **B** [Plato’s Allegory of the Cave](experiments/epistemology/allegory-of-the-cave.md) — How does the mind move from taking appearances for reality to grasping what is genuinely real, and what makes that movement hard? *Type: analogy.*
- **B** [Russell’s Five-Minute World](experiments/epistemology/russells-five-minute-world.md) — A newly created world with apparent memories tests the difference between present evidence and the past it represents. *Type: thought experiment.*
- **I** [The Cleverly Disguised Mule](experiments/epistemology/disguised-mule.md) — If you know something, and you know that it implies something else, must you also know the implied claim? *Type: thought experiment.*
- **B** [The Dream Argument](experiments/epistemology/dream-argument.md) — Dreams challenge the assumption that compelling present experience guarantees wakefulness. *Type: argument.*
- **A** [The Lottery Paradox](experiments/epistemology/lottery-paradox.md) — Can it be rational to believe each of a set of claims that you know cannot all be true, and what should we say about the relation between high probability and belief? *Type: paradox.*
- **I** [The Simulation Argument](experiments/epistemology/simulation-argument.md) — Given some assumptions about technology and consciousness, how likely is it that our experiences are those of simulated beings? *Type: argument.*

### Logic, Language, and Paradoxes

- **B** [Achilles and the Tortoise](experiments/logic/achilles-and-tortoise.md) — An infinite sequence of catch-up stages seems to prevent a faster runner from overtaking a slower one. *Type: paradox.*
- **B** [Buridan’s Ass](experiments/logic/buridans-ass.md) — Perfectly balanced alternatives test whether choosing requires a reason favoring one specific option. *Type: thought experiment.*
- **A** [Fitch’s Paradox of Knowability](experiments/logic/knowability-paradox.md) — Does the plausible thesis that all truths are knowable commit us to the implausible thesis that all truths are known? *Type: paradox.*
- **I** [Hesperus and Phosphorus](experiments/logic/hesperus-and-phosphorus.md) — If two names refer to the same object, why can an identity statement using them be informative while another is trivial? *Type: puzzle.*
- **A** [Kripke’s Quus](experiments/logic/quus-rule-following.md) — What fact about you, past or present, makes it the case that you meant plus and not quus? *Type: argument.*
- **A** [Quine’s Gavagai](experiments/logic/gavagai.md) — Is there a fact of the matter about what a word refers to, beyond what is settled by how speakers behave? *Type: thought experiment.*
- **I** [Russell’s Paradox](experiments/logic/russells-paradox.md) — The set of all sets that are not members of themselves undermines unrestricted set formation. *Type: paradox.*
- **B** [Sorites: When Does a Heap Begin?](experiments/logic/sorites.md) — A sequence of individually tiny changes challenges the boundaries of vague concepts. *Type: paradox.*
- **I** [The Grelling–Nelson Paradox (Heterological Words)](experiments/logic/grelling-nelson-paradox.md) — How can a perfectly well-defined word lead to a contradiction, and what must be restricted to avoid it? *Type: paradox.*
- **I** [The Liar Paradox](experiments/logic/liar.md) — A sentence that denies its own truth exposes tension in familiar principles of truth and inference. *Type: paradox.*
- **A** [The Unexpected Hanging / Surprise Test](experiments/logic/unexpected-hanging.md) — An announcement about what cannot be known seems to undermine the reasoning used to predict it. *Type: paradox.*
- **I** [Zeno’s Arrow](experiments/logic/zenos-arrow.md) — If a moving object is at rest at each instant, what makes it a moving object? *Type: paradox.*
- **B** [Zeno’s Dichotomy](experiments/logic/zenos-dichotomy.md) — How can a journey be completed if it can always be divided into infinitely many smaller stages? *Type: paradox.*

### Time, Causality, and Free Will

- **A** [Aristotle’s Sea Battle](experiments/time-and-causality/sea-battle.md) — Can statements about contingent future events be true or false now without making the future fixed? *Type: puzzle.*
- **A** [Frankfurt Cases](experiments/time-and-causality/frankfurt-cases.md) — A counterfactual intervener tests whether responsibility requires being able to act otherwise. *Type: thought experiment.*
- **I** [Laplace’s Demon](experiments/time-and-causality/laplaces-demon.md) — An ideal intelligence makes vivid the claim that a complete state and laws fix a whole history. *Type: thought experiment.*
- **A** [McTaggart’s Paradox of Time](experiments/time-and-causality/mctaggarts-paradox.md) — Is there a coherent notion of time that includes real change, and if not, is time real? *Type: argument.*
- **A** [Newcomb’s Problem](experiments/time-and-causality/newcomb.md) — A reliable prior prediction pits one-boxing against the apparent dominance of taking both boxes. *Type: puzzle.*
- **I** [Nietzsche’s Eternal Recurrence](experiments/time-and-causality/eternal-recurrence.md) — How would you feel about your life if you had to live it again without change, and what does your answer show about how you value it? *Type: thought experiment.*
- **A** [Pereboom’s Four-Case Argument](experiments/time-and-causality/four-case-argument.md) — If Plum is not responsible in Case 1, is there any relevant difference that would make him responsible in Case 4? *Type: argument.*
- **I** [The Bootstrap / Causal-Loop Paradox](experiments/time-and-causality/bootstrap.md) — A message circulating through time can seem to have no original author without being contradictory. *Type: paradox.*
- **A** [The Consequence Argument](experiments/time-and-causality/consequence-argument.md) — An argument about fixed pasts and laws tests whether determined agents can do otherwise. *Type: argument.*
- **I** [The Grandfather Paradox](experiments/time-and-causality/grandfather-paradox.md) — A traveler’s attempt to prevent their own ancestry tests the consistency of a single history. *Type: paradox.*
- **B** [The Idle Argument](experiments/time-and-causality/idle-argument.md) — If the future is already fixed, does it follow that nothing we do matters? *Type: argument.*

### Physics and the Universe

- **I** [Einstein Chases a Light Beam](experiments/physics/einsteins-light-beam.md) — A hypothetical pursuit of light exposes tension between classical motion and electromagnetic waves. *Type: thought experiment.*
- **B** [Einstein’s Elevator](experiments/physics/einsteins-elevator.md) — An enclosed cabin makes gravitational weight and acceleration locally difficult to distinguish. *Type: thought experiment.*
- **I** [Einstein’s Train and the Relativity of Simultaneity](experiments/physics/einsteins-train.md) — If both observers measure light as travelling at the same speed, can they agree on which events are simultaneous? *Type: thought experiment.*
- **B** [Galileo’s Ship](experiments/physics/galileos-ship.md) — If nothing that happens inside a smoothly moving cabin reveals the motion, what does it mean to say that the ship, or the Earth, is moving? *Type: thought experiment.*
- **B** [Galileo’s Tied Falling Bodies](experiments/physics/galileos-falling-bodies.md) — Tying a heavy and a light body together challenges weight-proportional falling speeds. *Type: thought experiment.*
- **I** [Heisenberg’s Microscope](experiments/physics/heisenbergs-microscope.md) — Is the uncertainty principle a limit on what measurement can reveal, or a feature of quantum systems themselves? *Type: thought experiment.*
- **A** [Loschmidt’s Reversibility Objection](experiments/physics/loschmidt-reversibility.md) — If the underlying laws do not distinguish past from future, why does entropy increase in one direction of time? *Type: thought experiment.*
- **I** [Maxwell’s Demon](experiments/physics/maxwells-demon.md) — A selective gatekeeper tests the thermodynamic cost of controlling microscopic motion. *Type: thought experiment.*
- **I** [Newton’s Bucket](experiments/physics/newtons-bucket.md) — If the water’s concavity does not depend on motion relative to the bucket, what does it depend on? *Type: thought experiment.*
- **I** [Schrödinger’s Cat](experiments/physics/schrodingers-cat.md) — A microscopic superposition is amplified into apparently incompatible descriptions of a cat. *Type: thought experiment.*
- **A** [The Einstein–Podolsky–Rosen Argument](experiments/physics/epr.md) — Perfect correlations challenge the joint assumptions of locality and a complete wave-function description. *Type: thought experiment.*
- **A** [The Hole Argument](experiments/physics/hole-argument.md) — Does general relativity force us to say either that spacetime points lack an identity apart from the fields on them, or that the theory is indeterministic? *Type: argument.*
- **I** [The Twin Paradox](experiments/physics/twin-paradox.md) — Twins following different spacetime paths can reunite with different elapsed ages. *Type: thought experiment.*
- **A** [Wigner’s Friend](experiments/physics/wigners-friend.md) — One observer records a result while another treats the whole laboratory quantum mechanically. *Type: thought experiment.*

### Mathematics and Probability

- **I** [Bertrand’s Random Chord Paradox](experiments/mathematics/bertrands-paradox.md) — Different precise procedures for choosing a “random chord” yield different probabilities. *Type: puzzle.*
- **B** [Galileo’s Paradox of the Infinite](experiments/mathematics/galileos-paradox.md) — Can an infinite collection have as many members as one of its own proper parts? *Type: paradox.*
- **B** [Hilbert’s Hotel](experiments/mathematics/hilberts-hotel.md) — A fully occupied infinite hotel can accommodate more guests without evicting anyone. *Type: thought experiment.*
- **I** [Simpson’s Paradox](experiments/mathematics/simpsons-paradox.md) — How can a treatment do better in every subgroup but worse overall, and which comparison should guide a decision? *Type: paradox.*
- **A** [Sleeping Beauty](experiments/mathematics/sleeping-beauty.md) — Memory loss separates uncertainty about a coin from uncertainty about which awakening is occurring. *Type: thought experiment.*
- **B** [The Monty Hall Problem](experiments/mathematics/monty-hall.md) — Switching wins twice as often when an informed host always reveals an unchosen losing door. *Type: puzzle.*
- **I** [The St. Petersburg Paradox](experiments/mathematics/st-petersburg-paradox.md) — A finite payout on every completed play can nevertheless have infinite expected monetary value. *Type: puzzle.*
- **A** [The Two Envelopes Problem](experiments/mathematics/two-envelopes.md) — A tempting switching calculation hides an unjustified conditional probability assignment. *Type: puzzle.*
- **I** [Thomson’s Lamp](experiments/mathematics/thomsons-lamp.md) — Is it possible to complete an infinite sequence of actions in a finite time, and if so, what determines the state at the end? *Type: paradox.*

### Economics and Decision Theory

- **B** [Keynes’s Beauty Contest](experiments/economics/keynesian-beauty-contest.md) — Winning may depend on predicting others’ predictions rather than expressing your own judgment. *Type: model.*
- **A** [Pascal’s Mugging](experiments/economics/pascals-mugging.md) — Should a rational agent who maximizes expected value hand over the wallet, and if not, what must be changed in the theory? *Type: puzzle.*
- **I** [Pascal’s Wager](experiments/economics/pascals-wager.md) — Can a calculation of expected benefit make it rational to commit to a belief or way of life? *Type: argument.*
- **I** [The Allais Paradox](experiments/economics/allais-paradox.md) — A preference for certainty can conflict with the independence axiom across paired lotteries. *Type: puzzle.*
- **I** [The Ellsberg Paradox](experiments/economics/ellsberg-paradox.md) — Choices involving an unknown color mixture challenge a single precise probability representation. *Type: puzzle.*
- **B** [The Prisoner’s Dilemma](experiments/economics/prisoners-dilemma.md) — Individually dominant choices can leave both players worse off than mutual cooperation. *Type: model.*
- **I** [The Stag Hunt](experiments/economics/stag-hunt.md) — When cooperation is best for everyone but risky, what lets people trust each other enough to coordinate? *Type: model.*
- **B** [The Tragedy of the Commons](experiments/economics/tragedy-of-the-commons.md) — Private gains and widely shared costs can encourage overuse of an unmanaged resource. *Type: model.*

### Artificial Intelligence and Machine Ethics

- **I** [Blockhead](experiments/artificial-intelligence/blockhead.md) — If a system’s behaviour is indistinguishable from an intelligent being’s, is that enough to say it is intelligent? *Type: thought experiment.*
- **I** [The AI Box Scenario](experiments/artificial-intelligence/ai-box.md) — A text-only channel may still let a confined system influence decisions outside its enclosure. *Type: thought experiment.*
- **I** [The Frame Problem](experiments/artificial-intelligence/frame-problem.md) — How can an agent with limited resources keep track of what is relevant to a change and ignore the rest? *Type: puzzle.*
- **A** [The Lucas–Penrose Argument](experiments/artificial-intelligence/lucas-penrose-argument.md) — Does Gödel’s theorem show that human mathematical understanding cannot be captured by any formal system or computer program? *Type: argument.*
- **I** [The Orthogonality Thesis](experiments/artificial-intelligence/orthogonality-thesis.md) — Is there any necessary connection between how intelligent an agent is and what it ultimately wants? *Type: argument.*
- **B** [The Paperclip Maximizer](experiments/artificial-intelligence/paperclip-maximizer.md) — A highly capable system pursues a simple objective without caring about what people value. *Type: thought experiment.*
- **I** [The Symbol Grounding Problem](experiments/artificial-intelligence/symbol-grounding.md) — How can the symbols of a system have meaning that does not depend on someone interpreting them? *Type: puzzle.*
- **B** [The Turing Test](experiments/artificial-intelligence/turing-test.md) — A text-mediated imitation game makes one question about machine intelligence operational. *Type: model.*

### Society, Justice, and Political Philosophy

- **A** [Arrow’s Impossibility Theorem](experiments/society-and-justice/arrows-impossibility-theorem.md) — Is there any fair way to combine individual rankings into a collective ranking? *Type: model.*
- **A** [Dworkin’s Resource Auction](experiments/society-and-justice/dworkins-auction.md) — An auction with equal purchasing power asks how equal concern can accommodate different ambitions. *Type: thought experiment.*
- **A** [Sen’s Paradox of the Paretian Liberal](experiments/society-and-justice/sens-liberal-paradox.md) — Can a society respect both a minimal right to personal liberty and the principle that it should adopt what everyone prefers? *Type: paradox.*
- **I** [The Condorcet Paradox](experiments/society-and-justice/condorcet-paradox.md) — Can majority rule produce a collective preference that is circular, and what should a group do about it? *Type: paradox.*
- **I** [The Leveling-Down Objection](experiments/society-and-justice/leveling-down.md) — Making the better-off worse off without helping anyone tests whether equality is valuable in itself. *Type: thought experiment.*
- **B** [The Ring of Gyges](experiments/society-and-justice/ring-of-gyges.md) — Invisibility removes ordinary accountability and asks whether justice remains worth choosing. *Type: thought experiment.*
- **B** [The State of Nature](experiments/society-and-justice/state-of-nature.md) — Imagine life without a common political authority to ask what can justify one. *Type: model.*
- **I** [The Veil of Ignorance and Original Position](experiments/society-and-justice/veil-of-ignorance.md) — Choose principles of justice without knowing which social position you will occupy. *Type: thought experiment.*
- **I** [Wilt Chamberlain’s Earnings](experiments/society-and-justice/wilt-chamberlain.md) — Voluntary payments to a popular player challenge the permanent maintenance of a distributive pattern. *Type: thought experiment.*

### Science, Biology, and Evolution

- **I** [Darwin’s Aquatic Bear Scenario](experiments/science-and-biology/darwins-aquatic-bear.md) — A speculative transition from aquatic feeding to whale-like form illustrates both possibility and evidential limits. *Type: thought experiment.*
- **I** [Darwin’s Imagined Gradations of the Eye](experiments/science-and-biology/darwins-eye.md) — A sequence of useful intermediate structures challenges an inference from complexity to impossibility. *Type: argument.*
- **I** [Leslie’s Firing Squad](experiments/science-and-biology/leslies-firing-squad.md) — When our existence depends on a rare condition, does the fact that we could only observe it in that case remove the need for an explanation? *Type: analogy.*
- **B** [Paley’s Watch](experiments/science-and-biology/paleys-watch.md) — Does the appearance of design in living things support the conclusion that they were designed? *Type: analogy.*
- **I** [The Spandrels of San Marco](experiments/science-and-biology/spandrels-of-san-marco.md) — A useful architectural space illustrates why present function need not explain historical origin. *Type: argument.*

## Read critically

Try answering the scenario before reading the responses. Name the assumptions, change one, and explain why your answer does or does not change. Use the sources to investigate disputed interpretations. The [connections guide](CONNECTIONS.md) compares related cases without treating them as interchangeable.

For wider context, the [Stanford Encyclopedia of Philosophy](https://plato.stanford.edu/) and [Internet Encyclopedia of Philosophy](https://iep.utm.edu/) provide scholarly introductions. Individual entries link to more specific sources and identify their evidential scope.

## Contributing and academic integrity

Students, teachers, researchers, and curious readers are welcome. Start with [CONTRIBUTING.md](CONTRIBUTING.md), the [editorial guidelines](EDITORIAL_GUIDELINES.md), and the [code of conduct](CODE_OF_CONDUCT.md). Corrections need evidence; new entries need sources, original prose, and meaningful connections. Do not invent historical priority, imply consensus where there is disagreement, or mistake a memorable scenario for empirical proof.

The [dataset](data/experiments.json) and [JSON Schema](data/schema.json) support reuse. Run `python3 scripts/validate.py` to check structure and internal links. See [GETTING_STARTED.md](GETTING_STARTED.md) for local setup and checks. No backend, API key, Pages site, or paid service is required.

## License and acknowledgments

Original text, code, data, and SVG artwork are available under the [MIT license](LICENSE). External books and articles retain their own rights. See [SOURCES_AND_ATTRIBUTION.md](SOURCES_AND_ATTRIBUTION.md). This educational collection is not a substitute for original scholarship or independent expert review.

Thanks to the authors, scholars, editors, and institutions whose work makes these questions accessible. AI assistance supported research and drafting; source notes and the quality report make the limits of that process explicit. No endorsement by cited authors or institutions is implied.