The Emperor's New Mind: Concerning Computers, Minds, and the Laws of Physics (Oxford Landmark Science)

by Roger Penrose

However, there is something else involved in our use of the terms ‘cause’ and ‘effect’ which is not really a matter of which of the events referred to happen to lie in the past and which in the future. Let us imagine a hypothetical universe in which the same time-symmetric classical equations apply as those of our own universe, but for which behaviour of the familiar kind (e.g. shattering and spilling of water glasses) coexists with occurrences like the time-reverses of these. Suppose that, along with our more familiar experiences, sometimes water glasses do assemble themselves out of broken pieces, mysteriously fill themselves out of splashes of water, and then leap up on to tables; suppose also that, on occasion, scrambled eggs magically unscramble and de-cook themselves, finally to leap back into broken eggshells which perfectly assemble and seal themselves about their newly-acquired contents; that lumps of sugar can form themselves out of the dissolved sugar in sweetened coffee and then spontaneously jump from the cup into someone’s hand. If we lived in a world where such occurrences were commonplace, surely we would ascribe the ‘causes’ of such events not to fantastically improbable chance coincidences concerning correlated behaviour of the individual atoms, but to some ‘teleological effect’ whereby the self-assembling objects sometimes strive to achieve some desired macroscopic configuration. ‘Look!’, we would say, ‘It’s happening again. That mess is going to assembl...