William of Occam

William of Occam, also called William Ockham (Ockham also spelled 'Occam') (1285-1347 or 1349), was a medieval monk (a scholastic). The Macquarie Dictionary prefers the spelling 'Occam', so we have followed this guide.

Occam's Razor

Occam's razor, also spelled 'Ockham's razor', but also called 'law of economy' or 'law of parsimony', is a principle stated by William of Occam, that entities are not to be multiplied beyond necessity (non sunt multiplicanda entia praeter necessitatem).

This principle was, in fact, invoked before Occam by Durand de Saint-Pourcain, a French Dominican theologian and philosopher of dubious orthodoxy, who used it to explain that abstraction is the apprehension of some real entity. Galileo did something similar by defending the simplest hypothesis of the heavens, and other later scientists stated similar simplifying laws and principles.

It is called Occam's Razor because he mentioned the principle so frequently and employed it so sharply.

He used it:

  • To dispense with relations which he held to be nothing distinct from their foundation in things;
  • With efficient causality, which he tended to view merely as regular succession;
  • With motion, which is merely the reappearance of a thing in a different place;
  • With psychological powers distinct for each mode of sense;
  • With the presence of ideas in the mind of the Creator, which are merely the creatures themselves.

Thanks to Encyclopaedia Britannica, Inc., 1994

Occam's Razor links

For further discussion of the principle see the Article in www.weburbia.com 


Discussion about other early scientists who used the same principle in Notes by Lloyd Allison of Monash University