Occam's Razor: The Simplest Explanation Is Usually the Right One

William of Ockham, a 14th-century English friar, proposed a principle so useful that scientists, doctors, and detectives still use it daily: "Entities should not be multiplied beyond necessity." In modern terms: when you have competing explanations, the one that requires the fewest assumptions is probably correct.

This doesn't mean the simplest explanation is always right — sometimes reality is genuinely complex. But Occam's Razor works because each additional assumption in an explanation is an additional chance to be wrong. If theory A requires 3 assumptions and theory B requires 7, theory B has more potential failure points. The math of probability is on Occam's side.

Here's a practical example: you hear hoofbeats. Occam's Razor says think horses, not zebras (unless you're in Africa). This is so foundational in medicine that doctors call unlikely diagnoses "zebras." But the razor's real power is in preventing conspiracy thinking: any theory that requires hundreds of people to maintain perfect secrecy, complex coverups, and implausible coincidences is almost certainly wrong — not because conspiracies never happen, but because each added layer of complexity dramatically reduces probability.