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Single Idea 17855
[filed under theme 6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / f. Mathematical induction
]
Full Idea
Frege's account of the ancestral has made it possible, in effect, to define the natural numbers as entities for which induction holds.
Gist of Idea
It may be possible to define induction in terms of the ancestral relation
Source
report of Gottlob Frege (Begriffsschrift [1879]) by Crispin Wright - Frege's Concept of Numbers as Objects 4.xix
Book Ref
Wright,Crispin: 'Frege's Conception of Numbers' [Scots Philosophical Monographs 1983], p.161
A Reaction
This is the opposite of the approach in the Peano Axioms, where induction is used to define the natural numbers.
The
20 ideas
from 'Begriffsschrift'
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7622
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In 1879 Frege developed second order logic
[Frege, by Putnam]
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7729
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Frege replaced Aristotle's subject/predicate form with function/argument form
[Frege, by Weiner]
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9991
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For Frege the variable ranges over all objects
[Frege, by Tait]
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10536
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Frege's domain for variables is all objects, but modern interpretations first fix the domain
[Dummett on Frege]
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9950
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A quantifier is a second-level predicate (which explains how it contributes to truth-conditions)
[Frege, by George/Velleman]
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13609
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Frege produced axioms for logic, though that does not now seem the natural basis for logic
[Frege, by Kaplan]
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7730
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Frege introduced quantifiers for generality
[Frege, by Weiner]
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7742
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Frege reduced most quantifiers to 'everything' combined with 'not'
[Frege, by McCullogh]
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13824
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Proof theory began with Frege's definition of derivability
[Frege, by Prawitz]
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17855
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It may be possible to define induction in terms of the ancestral relation
[Frege, by Wright,C]
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10607
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Frege's logic has a hierarchy of object, property, property-of-property etc.
[Frege, by Smith,P]
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11008
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Existence is not a first-order property, but the instantiation of a property
[Frege, by Read]
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22280
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Frege's account was top-down and decompositional, not bottom-up and compositional
[Frege, by Potter]
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7741
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The predicate 'exists' is actually a natural language expression for a quantifier
[Frege, by Weiner]
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22270
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Frege changed philosophy by extending logic's ability to check the grounds of thinking
[Potter on Frege]
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8939
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We should not describe human laws of thought, but how to correctly track truth
[Frege, by Fisher]
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17745
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For Frege, 'All A's are B's' means that the concept A implies the concept B
[Frege, by Walicki]
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7728
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Frege has a judgement stroke (vertical, asserting or judging) and a content stroke (horizontal, expressing)
[Frege, by Weiner]
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4971
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I don't use 'subject' and 'predicate' in my way of representing a judgement
[Frege]
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16881
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The laws of logic are boundless, so we want the few whose power contains the others
[Frege]
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