Occam’s Razor

Imagine waking up one morning to find that your kitchen floor is covered in water. There are several possible explanations. Perhaps a pipe burst during the night. Perhaps someone accidentally left the faucet running. Or perhaps a hidden underground spring has somehow emerged beneath the house, flooding the kitchen from below.

All three are technically possible. But without additional evidence, the simplest explanation is usually the most reasonable starting point. This idea is known as Occam’s Razor, named after the 14th-century philosopher William of Ockham. Its basic principle is often summarized as: when several explanations account for the same evidence, prefer the one that requires the fewest unnecessary assumptions.

The principle is not actually saying that the simplest explanation is always true. A complicated explanation can certainly be correct. A doctor should not diagnose someone with an exotic disease simply because it is more interesting, but neither should they dismiss unusual symptoms when the evidence demands a more complicated explanation. Occam’s Razor is better understood as a rule for deciding where to begin when several explanations remain possible.

Its power becomes clearer in science. Suppose a new observation can be explained by adding one small adjustment to an existing theory, or by inventing several new forces, particles, and laws that exist nowhere else. Unless the evidence requires those additions, the first explanation is generally preferable. This does not prove it is correct; it simply avoids introducing complexity without a reason. Much of scientific progress comes from discovering that phenomena that once seemed unrelated can be explained by a smaller number of underlying principles.

But simplicity itself can be deceptive. The simplest explanation is not necessarily the one with the fewest words or the fewest components. A scientific theory may be mathematically complicated while providing a much simpler explanation of nature than several competing theories. Occam’s Razor therefore asks us to remove unnecessary assumptions, not to blindly choose whatever sounds easiest.

That distinction makes the principle useful far beyond science. Humans naturally look for complicated explanations when something unexpected happens, often because complexity feels more satisfying than uncertainty. Occam’s Razor offers a useful resistance to that instinct: before inventing an elaborate story to explain something, ask whether the evidence actually requires one. Sometimes the simplest explanation is not the most exciting—but that is precisely why it deserves to be considered first.