IFrom: Audi, Robert, ed . The Cambridge Dictionary of Philosophy, Cambridge University Press (2 nd Edition 1999). I
definition, specification of the meaning or, alter tually defines 'exactly one' as it occurs in natlvely, conceptual content. of an expression. 'There ts exactly one F'. Recursive defini For example, 'period of fourteen days' Is a delin· tions (see below) are an Important variety ltloo of 'fortnight'. Definitions have traditionally of contextual deflnltlon. Another impor been judged by rules like the following: tant application of contextual definition is Russell's theory of descriptions, which (1) A definition should not be too narrow. defines 'the' as It occurs In contexts of the 'Unmarried adult male psychlatrlst' is too form 'The so-and-so is such-and·such'. narrow a delinitlon for 'bachelor', for some coordinative definition: definition of a theoretical bachelors are not psychiatrists. 'Having term by non-theoretical terms: e.g., 'the vertebrae and a llver' is too narrow for forty-millionth part of the circumference of 'vertebrate', for, ~ven though all actual the earth' for 'meter'. vertebrate things have vertebrae and a definition by 9enus and species: When an expres liver, it is possible for a vertebrate thing to sion is said to be applicable to some but not lack a liver. all entities of a certain type and inapplica (2) A definition should not be too broad. ble to all entities not of that type, the type 'Unmarried adult' ls too broad a definition in question is the genus, and the subtype of for 'bachelor', for not all unmarried adults all and only those entities to which the ar~ bachelors. 'Featherless biped' is too expression Is applicable is the species: e.g., broad for 'human being', for even though In the definition 'rational animal' for all actual featherless bipeds are human 'human', the type animal is the genus and beings, it is possible for a featherless biped the subtype human Is the species. Each to be non-human. species is distinguished from any other of (3) The defining expression in a definition the same genus by a property called the dif- should (ideally) exactly match the degree ' ferentia. of vagueness of the expression being definition in use: specification of how an expres defined (except in a predsing de~tlon). sion is used or what It is used to express: 'Adult female' for 'woman' does not vlo· e.g., 'uttered to express astonishment' for late this rule, but 'female at least eighteen 'my goodness'. Wittgenstein emphasized years old' for 'woman' does. . the importance of definition in use In his (4) A definition should not be circular. If 'desir· use theory of meaning. able' defines •good' and 'good' defines definition per genus et differentiam: definition by 'desirable'; these definitions are circular. genus and difference; same as definition by genus and species. Definitions fall into at least· the following explicit definition: definition that makes It clear kinds: that it is a definition and identifies the analytical definition: definition whose corre· expression being defined as such: e.g., spondlng blcond.itional is analytlc or gives 'Father' means 'male parent'; 'For any x, x an analysis of the definiendum: e.g., 'female is a father by definition if and only If x is a fox.' for 'vixen', where the corresponding male parent'. bkonditional 'For any x, x ls a vixen if and implicit definition: definition that ls not an only if x is a female fox' ls analytic; 'true in explicit definition. all possible worlds' for 'necessarily true', lexical definition: definition of the kind com where the corresponding bicondltional 'For monly thought appropriate for dictionary any P, Pis necessarily true if and only if Pis definitions of natural language terms, true in all possible worlds' gives an analysis namely, a specification of their conven- · of the definlendum; tional meaning. contextual definition: definition of an expression nominal definition: definition of a noun (usually as It occurs in a larger expression: e.g., 'If it a common noun), giving its linguistic is not the case that Q, then P' contextually meaning. Typically it Is in terms of defines 'unless' as It occurs In 'P unless Q': macrosenslble characteristics: e.g., 'yellow 'There is at least one entity that is P and ts malleable metal' for 'gold'. Locke spoke of identical with any entity that is F contex· nominal essence and contrasted it with real essence. ostensive definition: definition by an example In which the referent is specified by pointing or showing in some way: e.g., • 'Red' Is th color,· where the word 'that' is accomp • addition: 'Ox n = o. (m + 1) x n = (m x n) nied with a gesture pointing to a pntcl\ + n. Nothing else is the result of multiplying colored cloth; • 'Pain' means this,• wh Integers'. The base clause tells us, e.g., that 0 't~is' Is accompanied with an inse~lon 0~~ x 4 .., O. The recursive clause tells us, e.g., pm t.hrough the hearer's skin; • '[<.ingal'OO\ that (0 + 1) x 4 = (0 x 4) + 4. We then apphes to all and only animals like tltat' know that 1 X 4 = 0 + 4 = 4. Likewise, e.g .. where 'that' is accompanied by p lnting 2 x 4 = (1 + 1) x 4; (1 x 4) + 4 = 4 + a particular kangaroo. 4=8. persuasive definition: definition designed to a[!e '4 fpuJot/V( d(finition: definition regardless Of I.he or appeal to the psychological states of th • ordinary or usual conceptual conrenr of the party to whom the definition is given, ex:presslou defined. It postulates a content, that a claim will appear more plausible 1 rather than aiming to capture the content the party than it is: e.g., 'seU-se rvtn already associated wlth the expres~ion . Any manipulator' for 'politician', where th cxpllcil definition that introduces a new claim in question is that all politicians • expression into the language Is a s1ipulat!vc immoral. definition: e.g., *For the purpose of oul' dis· precis~ng ~ejinition: definition of a vague expl'esr , cuss!.on 'ex.lstent' means 'perceivable' •; s10n mtended to reduce its vagueness: e. · ~By 'zoobcedoobah' we shall mean 'vain 'snake longer than half a meter and shortcz umiUlonairc who is addicted to alcohol'." than two meters' for 'snake of averag' 011ymol{S definition: definition of a word (or length'; 'having assets ten thousand times . other linguistic expression) by another the median figure' for 'wealthy'. ' word synonymous with it: e.g .. 'buy' for prescriptive definition: stipulative definition lhatl 'purchase'.; 'madness' for 'insanity'. in a recommendatory way, gives a n meaning to an expression with a prcvlousl , established meaning: e.g., 'male whose prt mary sexual preference is for other males' for 'gay'. real definition: specification of the rnetaphysi cally necessar.y and sufficient condition lo' being the kind of thing a noun (usually common noun) designates: e.g., 'elemen with atomic number 79' for 'gold'. Lo - spoke of real essence and contrasted it wit nominal essence. recursive definition (also called inductive tle1lni ~' tion and definition by recursion): JeDn ltJon in three clauses in which ( 1) the expression• defined Is applied to certain particular Items (the base clause); (2) a rule is given rar{ reaching further items to which the expres-· sion applies (the recursive, or Inductive;· clause); and (3) it ls stated that the expres• slon applies to nothing else (the clomre clause). E.g., 'John's parents are John's nn· cestors; any parent of John's ancestor Js: John's ancestor; nothing else is .Jabn't1 ancestor'. By the base clause, John's mother and father are John's ancestors. Then by rhe recursive clause, John's mother's pnrcntf and John's father's parents are Jo hn '~ ancestors; so are their parents, and so on. ' Finally, by the last (closure) clause, these' people exhaust John's ancestors. The fol· lowing defines multiplication in tenns o '