Methodological principle of parsimony in scientific explanation.
Traditionally attributed to William of Ockham , the principle prescribes that entities are not to be multiplied beyond necessity. In practice, this means that if a phenomenon can be explained without assuming the existence of an entity, then philosophers and scientists should not assume the entity's existence. The history of science provides many examples of the principle's application (e.g., the rejection by scientists of the hypothesis of a luminiferous ether in response to Albert Einstein 's Special Theory of Relativity). See also materialism .