Occam's razor: a standalone construct

The principle is named for the English Franciscan friar and logician William of Ockham (c. 1287 to 1347), who argued repeatedly in his logical and theological writings that a plurality of entities or causes should not be posited without necessity, so that of two accounts fitting the same facts the leaner one is to be preferred. The now-familiar Latin formula, that entities should not be multiplied beyond necessity, and the name razor itself both postdate Ockham and were attached to the idea by later writers, though the rule of parsimony they capture is the one Ockham used. The modern philosophical treatment, developed by Elliott Sober, separates the razor of silence, which counsels staying agnostic about entities a theory does not need, from the razor of denial, which counsels rejecting them, and asks when each is justified. In contemporary methodology the same preference for fewer free assumptions is made precise in model selection, where measures such as the Akaike information criterion penalise added parameters and so tie simplicity to expected predictive accuracy. What makes the razor a landmark is its reach: it is a general norm of theory choice invoked across the sciences and in everyday reasoning, guiding which of several adequate explanations to hold without itself claiming that the simpler one is always true.[1][2][3][4]

Unit

A methodological norm of theory choice: favour the explanation that requires the fewest unnecessary assumptions

Recovery means

Not applicable

Measured by

Applied by comparing rival explanations or models on the number of independent assumptions, entities, or free parameters they require, and made formal in model-selection criteria that penalise added parameters