Combining Texts

All the ideas for 'The Question of Ontology', 'The Artworld' and 'Alfred Tarski: life and logic'

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22 ideas

4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX
10147 The Axiom of Choice is consistent with the other axioms of set theory [Feferman/Feferman]
10148 Axiom of Choice: a set exists which chooses just one element each of any set of sets [Feferman/Feferman]
10149 Platonist will accept the Axiom of Choice, but others want criteria of selection or definition [Feferman/Feferman]
10150 The Trichotomy Principle is equivalent to the Axiom of Choice [Feferman/Feferman]
10146 Cantor's theories needed the Axiom of Choice, but it has led to great controversy [Feferman/Feferman]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
10158 A structure is a 'model' when the axioms are true. So which of the structures are models? [Feferman/Feferman]
10162 Tarski and Vaught established the equivalence relations between first-order structures [Feferman/Feferman]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
10159 Löwenheim-Skolem Theorem, and Gödel's completeness of first-order logic, the earliest model theory [Feferman/Feferman]
10160 Löwenheim-Skolem says if the sentences are countable, so is the model [Feferman/Feferman]
5. Theory of Logic / K. Features of Logics / 4. Completeness
10161 If a sentence holds in every model of a theory, then it is logically derivable from the theory [Feferman/Feferman]
5. Theory of Logic / K. Features of Logics / 7. Decidability
10156 'Recursion theory' concerns what can be solved by computing machines [Feferman/Feferman]
10155 Both Principia Mathematica and Peano Arithmetic are undecidable [Feferman/Feferman]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / c. Fregean numbers
12215 The existence of numbers is not a matter of identities, but of constituents of the world [Fine,K]
6. Mathematics / C. Sources of Mathematics / 1. Mathematical Platonism / b. Against mathematical platonism
12211 It is plausible that x^2 = -1 had no solutions before complex numbers were 'introduced' [Fine,K]
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / a. Mathematical empiricism
12209 The indispensability argument shows that nature is non-numerical, not the denial of numbers [Fine,K]
7. Existence / A. Nature of Existence / 1. Nature of Existence
12214 'Exists' is a predicate, not a quantifier; 'electrons exist' is like 'electrons spin' [Fine,K]
7. Existence / A. Nature of Existence / 4. Abstract Existence
12212 Just as we introduced complex numbers, so we introduced sums and temporal parts [Fine,K]
7. Existence / A. Nature of Existence / 6. Criterion for Existence
12216 Real objects are those which figure in the facts that constitute reality [Fine,K]
12218 Being real and being fundamental are separate; Thales's water might be real and divisible [Fine,K]
7. Existence / D. Theories of Reality / 1. Ontologies
12217 For ontology we need, not internal or external views, but a view from outside reality [Fine,K]
7. Existence / D. Theories of Reality / 11. Ontological Commitment / b. Commitment of quantifiers
12213 Ontological claims are often universal, and not a matter of existential quantification [Fine,K]
21. Aesthetics / B. Nature of Art / 6. Art as Institution
20328 A thing is only seen as art in an 'artworld', which has a theory and a history [Danto]