Occam’s razor is a logical and philosophical principle stated by the medieval scholar William of Ockham (1285–1347/49). It gives precedence to simplicity; that is to say, of two or more competing theories, the simpler explanation of an entity is to be preferred. The principle is also expressed as “Entities are not to be multiplied beyond necessity.”
In other words, Ockham used the principle to dispense with relations, which he held to be nothing distinct from their foundation in things. According to Ockham:
pluralitas non est ponenda sine necessitate
“Plurality should not be posited without necessity.”
Explanations can become needlessly complex. It could become coherent to add the involvement of say, leprechauns to any explanation, but Occam’s Razor would prevent such additions, unless they were causally necessary.
“The simplest hypothesis proposed as an explanation of phenomena is more likely to be the true one than is any other available hypothesis, that its predictions are more likely to be true than those of any other available hypothesis, and that it is an ultimate a priori epistemic principle that simplicity is evidence for truth.” – Richard Swinburne
Consider the following example: Two trees have fallen down during a windy night. There could be two possible explanations to account for the fallen trees:
- The wind has blown them down.
- Two meteorites have each taken one tree down, and after that hit each other and removed any trace of themselves – that, or those pesky leprechauns again.