Combining Texts

All the ideas for 'Investigations in the Foundations of Set Theory I', 'Existence and Quantification' and 'Spreading the Word'

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25 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 / D. Modal Logic ML / 1. Modal Logic
Quine says quantified modal logic creates nonsense, bad ontology, and false essentialism [Melia on Quine]
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]
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 / 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 / A. Overview of Logic / 7. Second-Order Logic
Various strategies try to deal with the ontological commitments of second-order logic [Hale/Wright on Quine]
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 / 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]
7. Existence / A. Nature of Existence / 3. Being / b. Being and existence
Philosophers tend to distinguish broad 'being' from narrower 'existence' - but I reject that [Quine]
7. Existence / A. Nature of Existence / 6. Criterion for Existence
All we have of general existence is what existential quantifiers express [Quine]
7. Existence / D. Theories of Reality / 11. Ontological Commitment / b. Commitment of quantifiers
Existence is implied by the quantifiers, not by the constants [Quine]
7. Existence / D. Theories of Reality / 11. Ontological Commitment / c. Commitment of predicates
Theories are committed to objects of which some of its predicates must be true [Quine]
7. Existence / D. Theories of Reality / 11. Ontological Commitment / d. Commitment of theories
Express a theory in first-order predicate logic; its ontology is the types of bound variable needed for truth [Quine, by Lowe]
Ontological commitment of theories only arise if they are classically quantified [Quine]
7. Existence / D. Theories of Reality / 11. Ontological Commitment / e. Ontological commitment problems
You can be implicitly committed to something without quantifying over it [Thomasson on Quine]
7. Existence / E. Categories / 1. Categories
In formal terms, a category is the range of some style of variables [Quine]
10. Modality / A. Necessity / 11. Denial of Necessity
Asserting a necessity just expresses our inability to imagine it is false [Blackburn]