the principle that the simplest explanation of an event or observation is the preferred explanation. Simplicity is understood in various ways, including the requirement that an explanation should (a) make the smallest number of unsupported assumptions, (b) postulate the existence of the fewest entities, and (c) invoke the fewest unobservable constructs. Also called economy principle; principle of economy; principle of parsimony. See elegant solution; Occam’s razor.