Combining Texts

All the ideas for 'fragments/reports', 'On Referring' and 'Alfred Tarski: life and logic'

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21 ideas

4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX
The Axiom of Choice is consistent with the other axioms of set theory [Feferman/Feferman]
Axiom of Choice: a set exists which chooses just one element each of any set of sets [Feferman/Feferman]
Platonist will accept the Axiom of Choice, but others want criteria of selection or definition [Feferman/Feferman]
The Trichotomy Principle is equivalent to the Axiom of Choice [Feferman/Feferman]
Cantor's theories needed the Axiom of Choice, but it has led to great controversy [Feferman/Feferman]
5. Theory of Logic / E. Structures of Logic / 1. Logical Form
There are no rules for the exact logic of ordinary language, because that doesn't exist [Strawson,P]
5. Theory of Logic / F. Referring in Logic / 2. Descriptions / c. Theory of definite descriptions
'The present King of France is bald' presupposes existence, rather than stating it [Strawson,P, by Grayling]
Russell asks when 'The King of France is wise' would be a true assertion [Strawson,P]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
A structure is a 'model' when the axioms are true. So which of the structures are models? [Feferman/Feferman]
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
Löwenheim-Skolem says if the sentences are countable, so is the model [Feferman/Feferman]
Löwenheim-Skolem Theorem, and Gödel's completeness of first-order logic, the earliest model theory [Feferman/Feferman]
5. Theory of Logic / K. Features of Logics / 4. Completeness
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
'Recursion theory' concerns what can be solved by computing machines [Feferman/Feferman]
Both Principia Mathematica and Peano Arithmetic are undecidable [Feferman/Feferman]
6. Mathematics / B. Foundations for Mathematics / 3. Axioms for Geometry
Archimedes defined a straight line as the shortest distance between two points [Archimedes, by Leibniz]
19. Language / A. Nature of Meaning / 6. Meaning as Use
The meaning of an expression or sentence is general directions for its use, to refer or to assert [Strawson,P]
19. Language / B. Reference / 3. Direct Reference / c. Social reference
Reference is mainly a social phenomenon [Strawson,P, by Sainsbury]
19. Language / B. Reference / 4. Descriptive Reference / b. Reference by description
If an expression can refer to anything, it may still instrinsically refer, but relative to a context [Bach on Strawson,P]
19. Language / B. Reference / 5. Speaker's Reference
Expressions don't refer; people use expressions to refer [Strawson,P]
If an utterance fails to refer then it is a pseudo-use, though a speaker may think they assert something [Strawson,P]