Combining Philosophers

All the ideas for H.Putnam/P.Oppenheim, Ernst Zermelo and John Hawthorne

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39 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
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 / 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]
8. Modes of Existence / C. Powers and Dispositions / 2. Powers as Basic
A categorical basis could hardly explain a disposition if it had no powers of its own [Hawthorne]
8. Modes of Existence / C. Powers and Dispositions / 5. Powers and Properties
Is the causal profile of a property its essence? [Hawthorne]
If properties are more than their powers, we could have two properties with the same power [Hawthorne]
Could two different properties have the same causal profile? [Hawthorne]
9. Objects / B. Unity of Objects / 3. Unity Problems / a. Scattered objects
If we accept scattered objects such as archipelagos, why not think of cars that way? [Hawthorne]
9. Objects / C. Structure of Objects / 2. Hylomorphism / b. Form as principle
We can treat the structure/form of the world differently from the nodes/matter of the world [Hawthorne]
9. Objects / D. Essence of Objects / 3. Individual Essences
An individual essence is a necessary and sufficient profile for a thing [Hawthorne]
9. Objects / E. Objects over Time / 4. Four-Dimensionalism
Four-dimensionalists say instantaneous objects are more fundamental than long-lived ones [Hawthorne]
9. Objects / F. Identity among Objects / 1. Concept of Identity
Our notion of identical sets involves identical members, which needs absolute identity [Hawthorne]
10. Modality / A. Necessity / 11. Denial of Necessity
A modal can reverse meaning if the context is seen differently, so maybe context is all? [Hawthorne]
11. Knowledge Aims / B. Certain Knowledge / 2. Common Sense Certainty
Commitment to 'I have a hand' only makes sense in a context where it has been doubted [Hawthorne]
13. Knowledge Criteria / A. Justification Problems / 2. Justification Challenges / c. Knowledge closure
How can we know the heavyweight implications of normal knowledge? Must we distort 'knowledge'? [Hawthorne]
We wouldn't know the logical implications of our knowledge if small risks added up to big risks [Hawthorne]
Denying closure is denying we know P when we know P and Q, which is absurd in simple cases [Hawthorne]
14. Science / D. Explanation / 2. Types of Explanation / j. Explanations by reduction
Six reduction levels: groups, lives, cells, molecules, atoms, particles [Putnam/Oppenheim, by Watson]
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]
26. Natural Theory / C. Causation / 7. Eliminating causation
Maybe scientific causation is just generalisation about the patterns [Hawthorne]
26. Natural Theory / D. Laws of Nature / 6. Laws as Numerical
We only know the mathematical laws, but not much else [Hawthorne]
27. Natural Reality / C. Space / 6. Space-Time
Modern metaphysicians tend to think space-time points are more fundamental than space-time regions [Hawthorne]