Occam’s razor

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A rule of thumb, attributed to 12th century Franciscan friar William of Occam, that recommends when being presented with competing hypotheses about the same prediction, one should choose the solution with that makes the fewest assumptions.

Richard Dawkins is very fond of using Occam’s razor to eviscerate God-botherers — to be fair to him, any explanation of anything predicated on an all-knowing, all-seeing, invisible and non-material creator is drawing a long bow — but by the same token, he does not seem to have noticed its application to fundamental physics, especially insofar as dark matter, the multiverse and unseen spacetime dimensions required by string theory are concerned.

That said, Occam’s razor is no principle of logic, but a convenient heuristic. There are plenty of examples where Occam would prefer the wrong explanation: Newton’s laws of motion, for example, do not require contorting the geometry of spacetime to the point where time is a variable and the speed of light constant, despite there being almost no hard evidence for it, but they have still been superseded by Einstein’s, which do.

See also

• Science
• Philosophy of science
• Hanlon’s razor of stupidity