Occam’s Razor

Have you used Occam’s razor in class?

Don’t worry, this isn’t about playing with razor blades.

Occam’s razor (sometimes known as Ockham’s razor) is also called law of economy or law of parsimony stated by the philosopher William of Ockham (1285–1349).

The term refers to the philosophical idea or scientific principle that of any given set of explanations for an event occurring, it is most likely that the simplest one is the correct one.

It is a guideline for helping us choose between two or more explanations and slicing through a problem or situation to eliminate unnecessary elements.

Given lots of explanations about something, the least complicated one is probably the right one and the others are just superfluous. This isn’t necessarily the shortest explanation either but the simplest. Occam’s razor is about shaving away any unnecessary complications.

It’s useful for using in classroom discussion and making sound judgments about the world around us. For example, you get home to find the pedal bin tipped over and rubbish is scattered all over the the floor.

Two possible explanations are:

a) The dog tipped the bin over because it was bored and had been left alone for too long

b) Someone broke into the house and sorted through the rubbish looking for personal bank details.

Explanation:  a) with no evidence that someone has been in your house the first explanation is more likely.

This is about considering the evidence. Extraordinary claims mean you need extraordinary evidence.

Ockham mentioned the principle so frequently and used it so sharply that it was called “Occam’s razor”.

We might know Occam’s razor through Arthur Conan Doyle’s Sherlock Holmes. His classic saying is an expression of the principle: “If you eliminate the impossible, whatever remains, however improbable, must be the truth.”

It’s not perfect and proves nothing as it is a general rule of thumb. It isn’t an operation of formal logic or law but serves instead as a heuristic device – a guide or a suggestion. It is however, a problem-solving principle which serves as a useful mental model and helps us compare explanations in terms of their relative plausibility.

This is a great tool for thinking and decision making and might better be called Occam’s eraser!

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