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Single Idea 9874

[filed under theme 5. Theory of Logic / G. Quantification / 4. Substitutional Quantification ]

Full Idea

The contradiction in Frege's system is due to the presence of second-order quantification, ..and Frege's explanation of the second-order quantifier, unlike that which he provides for the first-order one, appears to be substitutional rather than objectual.

Gist of Idea

Contradiction arises from Frege's substitutional account of second-order quantification

Source

comment on Gottlob Frege (Grundgesetze der Arithmetik 1 (Basic Laws) [1893], §25) by Michael Dummett - Frege philosophy of mathematics Ch.17

Book Ref

Dummett,Michael: 'Frege: philosophy of mathematics' [Duckworth 1991], p.217


A Reaction

In Idea 9871 Dummett adds the further point that Frege lacks a clear notion of the domain of quantification. At this stage I don't fully understand this idea, but it is clearly of significance, so I will return to it.

Related Idea

Idea 9871 Frege always, and fatally, neglected the domain of quantification [Dummett on Frege]


The 9 ideas from 'Grundgesetze der Arithmetik 1 (Basic Laws)'

Frege considered definite descriptions to be genuine singular terms [Frege, by Fitting/Mendelsohn]
Frege defined number in terms of extensions of concepts, but needed Basic Law V to explain extensions [Frege, by Hale/Wright]
Frege ignored Cantor's warning that a cardinal set is not just a concept-extension [Tait on Frege]
A concept is a function mapping objects onto truth-values, if they fall under the concept [Frege, by Dummett]
Frege took the study of concepts to be part of logic [Frege, by Shapiro]
Contradiction arises from Frege's substitutional account of second-order quantification [Dummett on Frege]
Real numbers are ratios of quantities, such as lengths or masses [Frege]
We can't prove everything, but we can spell out the unproved, so that foundations are clear [Frege]
My Basic Law V is a law of pure logic [Frege]