Occam's Razor - Explanation and examples

Cut through the crap with a tool from your mate, Occam.


What is Occam’s razor?

If Occam’s razor brings to mind images of stubbled gentlemen and shaving cream, you’re not actually that far off! Occam’s razor (also known as the ‘law of parsimony’) is a philosophical tool for ‘shaving off’ unlikely explanations. Essentially, when faced with competing explanations for the same phenomenon, the simplest is likely the correct one.

Namesake William of Occam said the best explanation of any phenomenon is the one that makes the fewest assumptions. A statement that includes many ‘ifs’ should trigger mental alarm bells: you should consider Occam’s razor and investigate it further.

Some argue that the scientific method was built upon the principles of Occam’s razor. Underdetermination says that for any theory in science there will always be at least one other rival theory that could conceivably be correct, so the scientific method uses Occam’s razor in order to circumvent this issue and choose a working hypothesis.

Remember, however, that Occam’s razor is a heuristic, a rule of thumb, to suggest which hypothesis is most likely to be true. It doesn’t prove or disprove, it simply leads you down the path that’s most likely to be correct. Also, ‘simplicity’ is often subject to heavy debate, so you and I might come to different conclusions when faced with a decision between the same 2 hypotheses.

Examples of Occam’s razor

This principle is popular among skeptics, a group of people inclined to keep an open mind and believe only what we can sense or what can be proven scientifically. But there are plenty of examples in our everyday lives too.

Occam’s razor tells us that we shouldn’t get sucked into a whirlpool of paranoia after scrolling through WebMD. “You have a headache?”, “Oh no… you might have the Black Death!” Sure, it’s true that one of the symptoms of the Black Death is a headache but, using Occam’s razor, it’s obviously much more likely that you’re dehydrated or suffering from a common cold.

Many Creationists use Occam’s razor to argue the existence of God. “Isn’t the simplest explanation of how the Earth was created that God created it?” they say. But atheists might counter that the existence of a divine being who created the world in just seven days is much less simple (and relies on more assumptions) than the big bang theory - a great example of how simplicity is in the eye of the beholder.

Occam’s razor is also often used to debunk conspiracy theories. Faced with the disappointing mess that is modern politics, how likely is it REALLY that reptilian aliens have infiltrated our government? The simpler explanation is a combination of corruption, incompetence and structural inefficiency.

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Written by Frankie Andersen-Wood