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Mental Model: Occam’s Razor

All things being equal, the simplest solution tends to be the best one.

Occam's razor recommends that, when faced with two equally good hypotheses, choose the simpler. The principle is attributed to 14th-century English logician, theologian and Franciscan friar, William of Ockham.

Said another way, Occam's razor encourages the reduction of unnecessary elements in a design or system to achieve maximum simplicity without compromising functionality.

Scientists use Occam's razor as a heuristic to guide development of theoretical models.However, be warned, those that live by Occam's razor will also perish from it.

The principle is often expressed in Latin as: entia non sunt multiplicanda praeter necessitatem.


In How the Universe Got Its Spots: Diary of a Finite Time in a Finite Space, Janna Levin writes:

I try to find a simple expression for my ideas. I figure if there is none, the ideas must be wrong. When I first started to work on topology I wondered about complex properties of spaces and didn’t take my own suggestions seriously until I realized the simple way to ask the question: is the universe infinite? Einstein’s simplest insights were profound. The simpler the insight, the more profound the conclusion.


Occam's Razor is part of the Farnam Street latticework of mental models.