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Single Idea 17608
[filed under theme 4. Formal Logic / F. Set Theory ST / 1. Set Theory
]
Full Idea
Starting from set theory as it is historically given ...we must, on the one hand, restrict these principles sufficiently to exclude as contradiction and, on the other, take them sufficiently wide to retain all that is valuable in this theory.
Gist of Idea
We take set theory as given, and retain everything valuable, while avoiding contradictions
Source
Ernst Zermelo (Investigations in the Foundations of Set Theory I [1908], Intro)
Book Ref
'From Frege to Gödel 1879-1931', ed/tr. Heijenoort,Jean van [Harvard 1967], p.200
A Reaction
Maddy calls this the one-step-back-from-disaster rule of thumb. Zermelo explicitly mentions the 'Russell antinomy' that blocked Frege's approach to sets.
The
14 ideas
from 'Investigations in the Foundations of Set Theory I'
13486
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Not every predicate has an extension, but Separation picks the members that satisfy a predicate
[Zermelo, by Hart,WD]
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13017
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Zermelo introduced Pairing in 1930, and it seems fairly obvious
[Zermelo, by Maddy]
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13015
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Zermelo used Foundation to block paradox, but then decided that only Separation was needed
[Zermelo, by Maddy]
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13020
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The Axiom of Separation requires set generation up to one step back from contradiction
[Zermelo, by Maddy]
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13487
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In ZF, the Burali-Forti Paradox proves that there is no set of all ordinals
[Zermelo, by Hart,WD]
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18178
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For Zermelo the successor of n is {n} (rather than n U {n})
[Zermelo, by Maddy]
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13027
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Zermelo believed, and Von Neumann seemed to confirm, that numbers are sets
[Zermelo, by Maddy]
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9627
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Different versions of set theory result in different underlying structures for numbers
[Zermelo, by Brown,JR]
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15924
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Predicative definitions are acceptable in mathematics if they distinguish objects, rather than creating them?
[Zermelo, by Lavine]
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10870
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ZFC: Existence, Extension, Specification, Pairing, Unions, Powers, Infinity, Choice
[Zermelo, by Clegg]
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13012
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Zermelo published his axioms in 1908, to secure a controversial proof
[Zermelo, by Maddy]
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17609
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Set theory can be reduced to a few definitions and seven independent axioms
[Zermelo]
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17608
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We take set theory as given, and retain everything valuable, while avoiding contradictions
[Zermelo]
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17607
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Set theory investigates number, order and function, showing logical foundations for mathematics
[Zermelo]
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