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Single Idea 22270

[filed under theme 1. Philosophy / F. Analytic Philosophy / 6. Logical Analysis ]

Full Idea

Frege's 1879 logic transformed philosophy because it greatly expanded logic's reach - what thought can achieve unaided - and hence compelled a re-examination of everything previously said about the grounds of thought when logic gives out.

Gist of Idea

Frege changed philosophy by extending logic's ability to check the grounds of thinking

Source

comment on Gottlob Frege (Begriffsschrift [1879]) by Michael Potter - The Rise of Analytic Philosophy 1879-1930 Intro

Book Ref

Potter,Michael: 'The Rise of Anaytic Philosophy 1879-1930' [Routledge 2020], p.1


A Reaction

I loved the gloss on logic as 'what thought can achieve unaided'. I largely see logic in terms of what is mechanically computable.


The 20 ideas from 'Begriffsschrift'

In 1879 Frege developed second order logic [Frege, by Putnam]
Frege replaced Aristotle's subject/predicate form with function/argument form [Frege, by Weiner]
For Frege the variable ranges over all objects [Frege, by Tait]
Frege's domain for variables is all objects, but modern interpretations first fix the domain [Dummett on Frege]
A quantifier is a second-level predicate (which explains how it contributes to truth-conditions) [Frege, by George/Velleman]
Frege produced axioms for logic, though that does not now seem the natural basis for logic [Frege, by Kaplan]
Frege introduced quantifiers for generality [Frege, by Weiner]
Frege reduced most quantifiers to 'everything' combined with 'not' [Frege, by McCullogh]
Proof theory began with Frege's definition of derivability [Frege, by Prawitz]
It may be possible to define induction in terms of the ancestral relation [Frege, by Wright,C]
Frege's logic has a hierarchy of object, property, property-of-property etc. [Frege, by Smith,P]
Existence is not a first-order property, but the instantiation of a property [Frege, by Read]
Frege's account was top-down and decompositional, not bottom-up and compositional [Frege, by Potter]
The predicate 'exists' is actually a natural language expression for a quantifier [Frege, by Weiner]
Frege changed philosophy by extending logic's ability to check the grounds of thinking [Potter on Frege]
We should not describe human laws of thought, but how to correctly track truth [Frege, by Fisher]
For Frege, 'All A's are B's' means that the concept A implies the concept B [Frege, by Walicki]
Frege has a judgement stroke (vertical, asserting or judging) and a content stroke (horizontal, expressing) [Frege, by Weiner]
I don't use 'subject' and 'predicate' in my way of representing a judgement [Frege]
The laws of logic are boundless, so we want the few whose power contains the others [Frege]