The Brain in a Vat
The Brain in a Vat imagines that all experience is generated by a computer, asking whether you can know that an external world exists as it appears.
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Thought Experiments in Philosophy
Enter carefully simplified scenarios that bring one philosophical problem into sharper focus. Test your first reaction, compare the reasons behind competing answers, and notice what changes when a crucial detail shifts—while remembering that an imagined case can clarify an argument without proving it.
The Chinese Room
The Chinese Room imagines a person producing perfect Chinese responses by following formal rules while understanding no Chinese, challenging the claim that computation alone is sufficient for understanding.
Follow this path →The Experience Machine
The Experience Machine asks whether you would exchange life in the ordinary world for perfectly convincing experiences of achievement, love, pleasure, and meaning.
Follow this path →The Gettier Problem
The Gettier Problem asks whether a person can hold a justified true belief yet still fail to know because the belief’s truth is connected to the evidence only by luck.
Follow this path →Mary's Room
Mary knows all the physical information about color vision while living without color experience; the puzzle asks whether seeing red teaches her something new.
Follow this path →The Prisoner’s Dilemma
The Prisoner’s Dilemma models a situation in which each person has a reason to defect whatever the other does, even though mutual cooperation would leave both better off.
Follow this path →The Ring of Gyges
The Ring of Gyges asks whether a person would remain just after gaining the power to act unseen and escape ordinary consequences for wrongdoing.
Follow this path →The Ship of Theseus
The Ship of Theseus asks whether an object remains the same when all its parts are gradually replaced. A second version of the puzzle imagines the discarded parts being rebuilt into another ship, forcing us to compare material, structural, historical, functional, and practical accounts of identity.
Follow this path →The Teletransporter
A teletransporter records a person's complete physical and psychological state, destroys the original body, and creates an exact counterpart elsewhere, raising the question of who arrives.
Follow this path →The Trolley Problem
A runaway trolley forces a choice between allowing five people to be struck and redirecting the danger toward one person, exposing conflicts among harm, rights, agency, and outcomes.
Follow this path →The Veil of Ignorance
The Veil of Ignorance asks people to choose principles for society without knowing which social position, abilities, aims, or generation they will occupy.
Follow this path →Zhuangzi’s Butterfly Dream
Zhuangzi’s Butterfly Dream unsettles confidence in a fixed standpoint by moving between Zhuang Zhou dreaming he is a butterfly and the possibility of a butterfly dreaming it is Zhuang Zhou.
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