Thought experiments

demons

• Laplace's demon (determinism physics) Original quotation: "We may regard the present state of the universe as the effect of its past and the cause of its future. An intellect which at a certain moment would know all forces that set nature in motion, and all positions of all items of which nature is composed, if this intellect were also vast enough to submit these data to analysis, it would embrace in a single formula the movements of the greatest bodies of the universe and those of the tiniest atom; for such an intellect nothing would be uncertain and the future just like the past would be present before its eyes."
• Maxwell's demon (thermodynamics physics) Original quotation: "... if we conceive of a being whose faculties are so sharpened that he can follow every molecule in its course, such a being, whose attributes are as essentially finite as our own, would be able to do what is impossible to us. For we have seen that molecules in a vessel full of air at uniform temperature are moving with velocities by no means uniform, though the mean velocity of any great number of them, arbitrarily selected, is almost exactly uniform. Now let us suppose that such a vessel is divided into two portions, A and B, by a division in which there is a small hole, and that a being, who can see the individual molecules, opens and closes this hole, so as to allow only the swifter molecules to pass from A to B, and only the slower molecules to pass from B to A. He will thus, without expenditure of work, raise the temperature of B and lower that of A, in contradiction to the second law of thermodynamics...." (Maxwell (1871), reprinted in Leff & Rex (1990) at p.4)
• Descartes' demon (philosophy) http://books.google.com/books?id=yMwiTTpwasgC&lpg=PP1&pg=PA15#v=onepage&q=demon&f=false
• Socrates' daemon (philosophy) http://books.google.com/books?id=A4ANAAAAYAAJ&dq=apology%20of%20socrates%20daemon&pg=PA267#v=onepage&q=daemon&f=false
• Bergson's Demon (philosophy)
• Compton's Demon (philosophy)
• William James' Demon (philosophy)
• Frankfurt's Demon (philosophy)
• Landé's Demon (physics)
• Lewis' Demon (philosophy)
• Loschmidt's Demon (physics)
• Morton's Demon (psychology?) http://en.wikipedia.org/wiki/Morton%27s_demon
• Nietzsche's Demon (philosophy)
• Popper's Demon (???)
• Russell's Demon (physics)
• Wiener's Demon (cybernetics)

monsters

• the monster group (math)
• a monster state (physics)
• Utility monster (philosophy)

other creatures and spirits

• Faddeev–Popov ghost (physics)
• Floating Man (philosophy)
• Brain in a vat (philosophy)
• gremlins (comsci general)
• ghost in the machine (philosophy)

curious animals

• Schrödinger's cat
• Infinite monkey theorem
• infinite pigeons in infinite holes
• Buridan's ass
• Buttered cat paradox
• wittgenstein duck rabbit
• wittgenstein beetle

curious objects and instruments

• gabriel's horn
• Feynman sprinkler
• Heisenberg's microscope
• Ladder paradox
• Newton's cannonball
• Sticky bead argument
• big book
• zeno's arrow
• indiscernibles (identity of)
• lucretius's spear
• mach's motionless chain
• feynman indestructible blocks as energy (physics)
• Brillouin's Flashlight
• Haidinger's brush

curious vehicles

• Galileo's ship (Salvatius Ship)
• Ship of Theseus

curious machines

• Abstract Machine (comsci)
• Turning Machine
• Turning Test for machines (comsci)
• Analytical Engine (comsci)
• Brainstorm machine (philosophy)
• Nozick's Experience machine (philosophy)
• perpetual motion machine (physics)
• bernard's body-exchange machine (philosophy)
• Marian Smoluchowski's machine (physics)
• leibniz's mill/machine (natural vs artificial) (philosophy)
• godel self referential machines (philosophy)
• machine as metaphor for: humans, mind, body, animals, universal law, universe itself (philosophy)
• rothstein well-informed heat engine (philosophy)
• Landauer reversible machines (philosophy)
• feynman irreversible machine (physics)
• szilard's Engine (physics)

curious places

• devil's staircase
• infinite library
• Plank of Carneades
• plato's cave (forms?)
• hume's missing shade of blue
• rule-ruled room
• Cocktail Party Effect
• Spotlight effect
• prison experiment

curious persons

• Elitzur–Vaidman bomb-tester
• Twin paradox
• the catholic cannibal
• Wigner's friend
• Prisoner's dilemma
• The Monkey and the Hunter
• Quantum suicide and immortality
• Two Generals' Problem
• Dining philosophers problem
• vexed Violinist (ethics)