Combining Philosophers

All the ideas for Hermarchus, Ernst Zermelo and Bert Leuridan

expand these ideas     |    start again     |     specify just one area for these philosophers


33 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]
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
The Axiom of Separation requires set generation up to one step back from contradiction [Zermelo, by Maddy]
Not every predicate has an extension, but Separation picks the members that satisfy a predicate [Zermelo, by Hart,WD]
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]
14. Science / D. Explanation / 2. Types of Explanation / e. Lawlike explanations
Generalisations must be invariant to explain anything [Leuridan]
14. Science / D. Explanation / 2. Types of Explanation / h. Explanations by function
Biological functions are explained by disposition, or by causal role [Leuridan]
14. Science / D. Explanation / 2. Types of Explanation / i. Explanations by mechanism
Mechanisms must produce macro-level regularities, but that needs micro-level regularities [Leuridan]
Mechanisms are ontologically dependent on regularities [Leuridan]
Mechanisms can't explain on their own, as their models rest on pragmatic regularities [Leuridan]
We can show that regularities and pragmatic laws are more basic than mechanisms [Leuridan]
14. Science / D. Explanation / 3. Best Explanation / b. Ultimate explanation
There is nothing wrong with an infinite regress of mechanisms and regularities [Leuridan]
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]
25. Social Practice / F. Life Issues / 6. Animal Rights
Animals are dangerous and nourishing, and can't form contracts of justice [Hermarchus, by Sedley]
26. Natural Theory / A. Speculations on Nature / 3. Natural Function
Rather than dispositions, functions may be the element that brought a thing into existence [Leuridan]
26. Natural Theory / D. Laws of Nature / 3. Laws and Generalities
Pragmatic laws allow prediction and explanation, to the extent that reality is stable [Leuridan]
26. Natural Theory / D. Laws of Nature / 4. Regularities / a. Regularity theory
Strict regularities are rarely discovered in life sciences [Leuridan]
26. Natural Theory / D. Laws of Nature / 11. Against Laws of Nature
A 'law of nature' is just a regularity, not some entity that causes the regularity [Leuridan]