Combining Philosophers

All the ideas for Rayo,A/Uzquiasno,G, Albert Casullo and Ernst Zermelo

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34 ideas

2. Reason / D. Definition / 8. Impredicative Definition
Predicative definitions are acceptable in mathematics if they distinguish objects, rather than creating them? [Zermelo, by Lavine]
4. Formal Logic / F. Set Theory ST / 1. Set Theory
We take set theory as given, and retain everything valuable, while avoiding contradictions [Zermelo]
Set theory investigates number, order and function, showing logical foundations for mathematics [Zermelo]
The two best understood conceptions of set are the Iterative and the Limitation of Size [Rayo/Uzquiano]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
ZFC: Existence, Extension, Specification, Pairing, Unions, Powers, Infinity, Choice [Zermelo, by Clegg]
Zermelo published his axioms in 1908, to secure a controversial proof [Zermelo, by Maddy]
Set theory can be reduced to a few definitions and seven independent axioms [Zermelo]
Zermelo made 'set' and 'member' undefined axioms [Zermelo, by Chihara]
For Zermelo's set theory the empty set is zero and the successor of each number is its unit set [Zermelo, by Blackburn]
Zermelo showed that the ZF axioms in 1930 were non-categorical [Zermelo, by Hallett,M]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / c. Axiom of Pairing II
Zermelo introduced Pairing in 1930, and it seems fairly obvious [Zermelo, by Maddy]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / h. Axiom of Replacement VII
Replacement was added when some advanced theorems seemed to need it [Zermelo, by Maddy]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / i. Axiom of Foundation VIII
Zermelo used Foundation to block paradox, but then decided that only Separation was needed [Zermelo, by Maddy]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / m. Axiom of Separation
Some set theories give up Separation in exchange for a universal set [Rayo/Uzquiano]
Not every predicate has an extension, but Separation picks the members that satisfy a predicate [Zermelo, by Hart,WD]
The Axiom of Separation requires set generation up to one step back from contradiction [Zermelo, by Maddy]
5. Theory of Logic / G. Quantification / 2. Domain of Quantification
We could have unrestricted quantification without having an all-inclusive domain [Rayo/Uzquiano]
Absolute generality is impossible, if there are indefinitely extensible concepts like sets and ordinals [Rayo/Uzquiano]
5. Theory of Logic / G. Quantification / 5. Second-Order Quantification
Perhaps second-order quantifications cover concepts of objects, rather than plain objects [Rayo/Uzquiano]
5. Theory of Logic / L. Paradox / 3. Antinomies
The antinomy of endless advance and of completion is resolved in well-ordered transfinite numbers [Zermelo]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
In ZF, the Burali-Forti Paradox proves that there is no set of all ordinals [Zermelo, by Hart,WD]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / e. Countable infinity
Zermelo realised that Choice would facilitate the sort of 'counting' Cantor needed [Zermelo, by Lavine]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / f. Zermelo numbers
For Zermelo the successor of n is {n} (rather than n U {n}) [Zermelo, by Maddy]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
Zermelo believed, and Von Neumann seemed to confirm, that numbers are sets [Zermelo, by Maddy]
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / e. Structuralism critique
Different versions of set theory result in different underlying structures for numbers [Zermelo, by Brown,JR]
10. Modality / A. Necessity / 11. Denial of Necessity
Maybe modal sentences cannot be true or false [Casullo]
10. Modality / D. Knowledge of Modality / 1. A Priori Necessary
If the necessary is a priori, so is the contingent, because the same evidence is involved [Casullo]
12. Knowledge Sources / A. A Priori Knowledge / 1. Nature of the A Priori
Epistemic a priori conditions concern either the source, defeasibility or strength [Casullo]
The main claim of defenders of the a priori is that some justifications are non-experiential [Casullo]
12. Knowledge Sources / A. A Priori Knowledge / 4. A Priori as Necessities
Analysis of the a priori by necessity or analyticity addresses the proposition, not the justification [Casullo]
12. Knowledge Sources / A. A Priori Knowledge / 10. A Priori as Subjective
Maybe imagination is the source of a priori justification [Casullo]
13. Knowledge Criteria / A. Justification Problems / 1. Justification / c. Defeasibility
'Overriding' defeaters rule it out, and 'undermining' defeaters weaken in [Casullo]
18. Thought / A. Modes of Thought / 6. Judgement / a. Nature of Judgement
We should judge principles by the science, not science by some fixed principles [Zermelo]
19. Language / F. Communication / 5. Pragmatics / a. Contextual meaning
The domain of an assertion is restricted by context, either semantically or pragmatically [Rayo/Uzquiano]