What does Occam's razor say?
Named for the 14th-century English friar William of Ockham, it boils down to: don't multiply assumptions beyond necessity. You "shave off" whatever an explanation doesn't need. Hear a bump in the night? Suspect the wind before you suspect a ghost.
How is it used in science and data work?
Heliocentrism eventually won out partly because it didn't need the elaborate epicycles of the Earth-centered model. In statistics and machine learning, the razor warns against models with so many parameters that they overfit the training data. It doesn't claim the simplest answer is always true—only that, with equal evidence, simpler is the better bet.
FAQ
- Is the simplest explanation always right?
- No. If the evidence supports a more complex explanation, go with the evidence.
- Did Ockham actually say it?
- The famous wording came later, but the idea appears repeatedly in his writing.
Sources reviewed: 2026-10-25
References
- William of Ockham. Summa Logicae (c. 1323).
- Sober, E. (2015). Ockham's Razors: A User's Manual. Cambridge University Press.