Nominal definitions vs real definitions Definition

in classical thought, definition taken statement of essence of thing. aristotle had object s essential attributes form essential nature , , definition of object must include these essential attributes.

the idea definition should state essence of thing led distinction between nominal , real essence, originating aristotle. in passage posterior analytics, says meaning of made-up name can known (he gives example goat stag ), without knowing calls essential nature of thing name denote, if there such thing. led medieval logicians distinguish between called quid nominis or whatness of name , , underlying nature common things names, called quid rei or whatness of thing . (early modern philosophers locke used corresponding english terms nominal essence , real essence ). name hobbit , example, meaningful. has quid nominis. 1 not know real nature of hobbits, if there such things, , real nature or quid rei of hobbits cannot known. contrast, name man denotes real things (men) have quid rei. meaning of name distinct nature thing must have in order name apply it.

this leads corresponding distinction between nominal , real definitions. nominal definition definition explaining word means, i.e. says nominal essence is, , definition in classical sense given above. real definition, contrast, 1 expressing real nature or quid rei of thing.

this preoccupation essence dissipated in of modern philosophy. analytic philosophy in particular critical of attempts elucidate essence of thing. russell described hopelessly muddle-headed notion .

more kripke s formalisation of possible world semantics in modal logic led new approach essentialism. insofar essential properties of thing necessary it, things possesses in possible worlds. kripke refers names used in way rigid designators.