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Single Idea 13886

[filed under theme 2. Reason / D. Definition / 2. Aims of Definition ]

Full Idea

Frege later became fastidious about definitions, and demanded that they must provide for every possible case, and that no function is properly determined unless its value is fixed for every conceivable object as argument.

Gist of Idea

Later Frege held that definitions must fix a function's value for every possible argument

Source

report of Gottlob Frege (Grundgesetze der Arithmetik 2 (Basic Laws) [1903]) by Crispin Wright - Frege's Concept of Numbers as Objects 3.xiv

Book Ref

Wright,Crispin: 'Frege's Conception of Numbers' [Scots Philosophical Monographs 1983], p.109


A Reaction

Presumably definitions come in degrees of completeness, but it seems harsh to describe a desire for the perfect definition as 'fastidious', especially if we are talking about mathematics, rather than defining 'happiness'.


The 12 ideas from 'Grundgesetze der Arithmetik 2 (Basic Laws)'

Later Frege held that definitions must fix a function's value for every possible argument [Frege, by Wright,C]
Real numbers are ratios of quantities [Frege, by Dummett]
A number is a class of classes of the same cardinality [Frege, by Dummett]
Frege's biggest error is in not accounting for the senses of number terms [Hodes on Frege]
Cardinals say how many, and reals give measurements compared to a unit quantity [Frege]
The modern account of real numbers detaches a ratio from its geometrical origins [Frege]
The first demand of logic is of a sharp boundary [Frege]
Only what is logically complex can be defined; what is simple must be pointed to [Frege]
We can't define a word by defining an expression containing it, as the remaining parts are a problem [Frege]
Formalism misunderstands applications, metatheory, and infinity [Frege, by Dummett]
Only applicability raises arithmetic from a game to a science [Frege]
If we abstract the difference between two houses, they don't become the same house [Frege]