# Sources — occams-razor

> *Primary and authoritative sources for the [occams-razor](../SKILL.md) skill.*

- Stanford Encyclopedia of Philosophy, *William of Ockham* — the razor as a methodological (not metaphysical) principle, "cautionary" rather than a proof; and that the popular formulation "entities must not be multiplied beyond necessity" is "nowhere to be found in his texts." https://plato.stanford.edu/entries/ockham/
- Encyclopædia Britannica, *Occam's razor* — origin in William of Ockham; the formulation "Pluralitas non est ponenda sine necessitate" ("plurality should not be posited without necessity"); the principle of parsimony. https://www.britannica.com/topic/Occams-razor
- Statistical-learning reading: the same principle appears formally as model selection / penalizing model complexity to avoid overfitting noise — preferring the model whose hypothesis space is least flexible while still fitting the data.
- "As simple as possible, but not simpler" is *commonly attributed to Einstein but unverified*; it is used here only as a popular phrasing of the over-shave guard, not cited as a source — per this skill's own rule, an attributed quote is not evidence.