Everyone loves a thought experiment, from Maxwell's demon to the classic bootstrap paradox. But there is one thought experiment – briefly banned by the Internet forum where it was first posted ...

a thought experiment to be tinkered with now and then, if only because the cool media and books that sometimes appear due to it.

Devised in 1935 by the Austrian physicist Erwin Schrödinger, this thought experiment was designed to shine a spotlight on the difficulty with interpreting quantum theory. Quantum theory is very ...