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2. Reason / D. Definition / 3. Types of Definition

[whether there are different sorts of definition]

11 ideas
You can't define particulars, because accounts have to be generalised [Aristotle]
     Full Idea: It is impossible to define particulars. …The fact is that an account is general.
     From: Aristotle (Metaphysics [c.324 BCE], 1040a33-)
     A reaction: Aristotle rejects attempts to define the Sun as possible counterexamples. Since this claims rests on the idea of an account [logos], I presume the point is actually that definitions are linguistic, and must use general words.
A nominal definition is of the qualities, but the real definition is of the essential inner structure [Leibniz]
     Full Idea: The essence of gold is what constitutes it and gives it the sensible qualities which let us recognize it and which make its nominal definition; but if we could explain this structure or inner constitution we would possess the real, causal definition.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 3.03)
     A reaction: This is the view which I am championing, particularly in the role of explanation in the whole game. Explanation and understanding are the hallmarks of the discovery of a real essence. However, a falsehood may explain things well. Tricky.
Only that which has no history is definable [Nietzsche]
     Full Idea: Only that which has no history is definable.
     From: Friedrich Nietzsche (On the Genealogy of Morals [1887], II.§13)
     A reaction: Too subtle to evaluate! It sounds as if it could be right, that some things are definable, but when the accretions of human history are interwoven into an identity, we can forget it.
A 'constructive' (as opposed to 'analytic') definition creates a new sign [Frege]
     Full Idea: We construct a sense out of its constituents and introduce an entirely new sign to express this sense. This may be called a 'constructive definition', but we prefer to call it a 'definition' tout court. It contrasts with an 'analytic' definition.
     From: Gottlob Frege (Logic in Mathematics [1914], p.210)
     A reaction: An analytic definition is evidently a deconstruction of a past constructive definition. Fregean definition is a creative activity.
A definition by 'extension' enumerates items, and one by 'intension' gives a defining property [Russell]
     Full Idea: The definition of a class or collection which enumerates is called a definition by 'extension', and one which mentions a defining property is called a definition by 'intension'.
     From: Bertrand Russell (Introduction to Mathematical Philosophy [1919], II)
     A reaction: In ordinary usage we take intensional definitions for granted, so it is interesting to realise that you might define 'tiger' by just enumerating all the tigers. But all past tigers? All future tigers? All possible tigers which never exist?
A decent modern definition should always imply a semantics [Hacking]
     Full Idea: Today we expect that anything worth calling a definition should imply a semantics.
     From: Ian Hacking (What is Logic? [1979], §10)
     A reaction: He compares this with Gentzen 1935, who was attempting purely syntactic definitions of the logical connectives.
A definition can be 'extensionally', 'intensionally' or 'sense' adequate [Gupta]
     Full Idea: A definition is 'extensionally adequate' iff there are no actual counterexamples to it. It is 'intensionally adequate' iff there are no possible counterexamples to it. It is 'sense adequate' (or 'analytic') iff it endows the term with the right sense.
     From: Anil Gupta (Definitions [2008], 1.4)
Traditional definitions are general identities, which are sentential and reductive [Gupta]
     Full Idea: Traditional definitions are generalized identities (so definiendum and definiens can replace each other), in which the sentential is primary (for use in argument), and they involve reduction (and hence eliminability in a ground language).
     From: Anil Gupta (Definitions [2008], 2.2)
Traditional definitions need: same category, mention of the term, and conservativeness and eliminability [Gupta]
     Full Idea: A traditional definition requires that the definiendum contains the defined term, that definiendum and definiens are of the same logical category, and the definition is conservative (adding nothing new), and makes elimination possible.
     From: Anil Gupta (Definitions [2008], 2.4)
Implicit definitions must be satisfiable, creative definitions introduce things, contextual definitions build on things [Fine,K, by Cook/Ebert]
     Full Idea: Fine distinguishes 'implicit definitions', where we must know it is satisfiable before it is deployed, 'creative definitions', where objects are introduced in virtue of the definition, ..and 'contextual definitions', based on established vocabulary.
     From: report of Kit Fine (The Limits of Abstraction [2002], 060) by R Cook / P Ebert - Notice of Fine's 'Limits of Abstraction' 3
     A reaction: Fine is a fan of creative definition. This sounds something like the distinction between cutting nature at the perceived joints, and speculating about where new joints might be inserted. Quite a helpful thought.
'Creative definitions' do not presuppose the existence of the objects defined [Fine,K]
     Full Idea: What I call 'creative definitions' are made from a standpoint in which the existence of the objects that are to be assigned to the terms is not presupposed.
     From: Kit Fine (The Limits of Abstraction [2002], II.1)