Don't forget randomness is still just a hypothesis


Anton Zeilinger's bold essay “The message of the quantum” (Nature 438, 743; 2005) claims “the discovery that individual events are irreducibly random is probably one of the most significant findings of the twentieth century.” But we should not forget that the claim of true randomness has not yet been backed by evidence. Neither Heisenberg's uncertainty principle nor Bell's inequality exclude the possibility, however small, that the Universe, including all observers inhabiting it, is in principle computable by a completely deterministic computer program, as first suggested by computer pioneer Konrad Zuse in 1967 (Elektron. Datenverarb. 8, 336–344; 1967).

The principle of Occam's razor, which is fundamental to theory-building, favours simple explanations (describable by few bits of information) over complex ones. But if the Universe's history really included many truly random events, an enormous amount of information would be necessary to describe all the random observations inexplicable by the known, simple, elegant, compactly describable laws of physics.

A few previous attempts at discovering a pseudo-random generator behind seemingly random physical events have failed (see T. Erber and S. Putterman Nature 318, 41–43; 1985). But as long as the randomness hypothesis has not been verified, physicists should keep trying to falsify it and search not only for statistical laws but also for deterministic rules explaining any type of hitherto unexplained apparent randomness.

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