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Ideas for 'works', 'The Limits of Abstraction' and 'Logic in Mathematics'

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5 ideas

2. Reason / D. Definition / 3. Types of Definition
'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)
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.
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.
2. Reason / D. Definition / 10. Stipulative Definition
Frege suggested that mathematics should only accept stipulative definitions [Frege, by Gupta]
     Full Idea: Frege has defended the austere view that, in mathematics at least, only stipulative definitions should be countenanced.
     From: report of Gottlob Frege (Logic in Mathematics [1914]) by Anil Gupta - Definitions 1.3
     A reaction: This sounds intriguingly at odds with Frege's well-known platonism about numbers (as sets of equinumerous sets). It makes sense for other mathematical concepts.
2. Reason / E. Argument / 6. Conclusive Proof
We must be clear about every premise and every law used in a proof [Frege]
     Full Idea: It is so important, if we are to have a clear insight into what is going on, for us to be able to recognise the premises of every inference which occurs in a proof and the law of inference in accordance with which it takes place.
     From: Gottlob Frege (Logic in Mathematics [1914], p.212)
     A reaction: Teachers of logic like natural deduction, because it reduces everything to a few clear laws, which can be stated at each step.