Philosophy
What is Occam's razor?
Occam's razor is the principle that, when several explanations fit the facts, the simplest one — with the fewest assumptions — is usually the best place to start. It doesn't guarantee truth, but it's a powerful guide in science and reasoning.
See it, don’t just read it.
Watch a 2-minute lesson with voice + animation that explains occam's razor.
Key things to understand
- 1Prefer the explanation that makes the fewest assumptions.
- 2It's a guideline for choosing between competing theories, not a proof.
- 3Simpler explanations are easier to test and less likely to be wrong by chance.
- 4It's named after medieval philosopher William of Ockham.
- 5It underpins the scientific habit of not multiplying assumptions needlessly.
Frequently asked questions
- Does Occam's razor mean the simplest answer is always true?
- No — it says the simplest adequate explanation is the best starting point, but stronger evidence can still favor a more complex one.
- Why prefer simpler explanations?
- They rest on fewer unproven assumptions, are easier to test, and have fewer ways to be accidentally wrong.
- Where is Occam's razor used?
- In science, medicine, detective work, and debugging — anywhere you choose among explanations that all fit the facts.