Combining Philosophers

All the ideas for Anaxarchus, Allan Gibbard and John von Neumann

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25 ideas

4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
Von Neumann defines each number as the set of all smaller numbers [Neumann, by Blackburn]
4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / f. Limitation of Size
Limitation of Size is not self-evident, and seems too strong [Lavine on Neumann]
4. Formal Logic / F. Set Theory ST / 8. Critique of Set Theory
Von Neumann wanted mathematical functions to replace sets [Neumann, by Benardete,JA]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / c. Priority of numbers
Von Neumann treated cardinals as a special sort of ordinal [Neumann, by Hart,WD]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
Von Neumann defined ordinals as the set of all smaller ordinals [Neumann, by Poundstone]
A von Neumann ordinal is a transitive set with transitive elements [Neumann, by Badiou]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / g. Von Neumann numbers
For Von Neumann the successor of n is n U {n} (rather than {n}) [Neumann, by Maddy]
Von Neumann numbers are preferred, because they continue into the transfinite [Maddy on Neumann]
Each Von Neumann ordinal number is the set of its predecessors [Neumann, by Lavine]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
All the axioms for mathematics presuppose set theory [Neumann]
9. Objects / B. Unity of Objects / 3. Unity Problems / c. Statue and clay
If a statue is identical with the clay of which it is made, that identity is contingent [Gibbard]
A 'piece' of clay begins when its parts stick together, separately from other clay [Gibbard]
Clay and statue are two objects, which can be named and reasoned about [Gibbard]
We can only investigate the identity once we have designated it as 'statue' or as 'clay' [Gibbard]
9. Objects / D. Essence of Objects / 7. Essence and Necessity / a. Essence as necessary properties
Essentialism is the existence of a definite answer as to whether an entity fulfils a condition [Gibbard]
9. Objects / D. Essence of Objects / 15. Against Essentialism
Essentialism for concreta is false, since they can come apart under two concepts [Gibbard]
9. Objects / E. Objects over Time / 12. Origin as Essential
A particular statue has sortal persistence conditions, so its origin defines it [Gibbard]
9. Objects / F. Identity among Objects / 6. Identity between Objects
Claims on contingent identity seem to violate Leibniz's Law [Gibbard]
9. Objects / F. Identity among Objects / 8. Leibniz's Law
Two identical things must share properties - including creation and destruction times [Gibbard]
Leibniz's Law isn't just about substitutivity, because it must involve properties and relations [Gibbard]
10. Modality / E. Possible worlds / 3. Transworld Objects / a. Transworld identity
Possible worlds identity needs a sortal [Gibbard]
Only concepts, not individuals, can be the same across possible worlds [Gibbard]
10. Modality / E. Possible worlds / 3. Transworld Objects / b. Rigid designation
Kripke's semantics needs lots of intuitions about which properties are essential [Gibbard]
13. Knowledge Criteria / D. Scepticism / 1. Scepticism
Anaxarchus said that he was not even sure that he knew nothing [Anaxarchus, by Diog. Laertius]
19. Language / B. Reference / 3. Direct Reference / b. Causal reference
Naming a thing in the actual world also invokes some persistence criteria [Gibbard]