Combining Philosophers

All the ideas for Anaxarchus, Keith Devlin and Kenneth Kunen

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26 ideas

1. Philosophy / B. History of Ideas / 5. Later European Thought
Logic was merely a branch of rhetoric until the scientific 17th century [Devlin]
4. Formal Logic / A. Syllogistic Logic / 2. Syllogistic Logic
'No councillors are bankers' and 'All bankers are athletes' implies 'Some athletes are not councillors' [Devlin]
4. Formal Logic / B. Propositional Logic PL / 1. Propositional Logic
Modern propositional inference replaces Aristotle's 19 syllogisms with modus ponens [Devlin]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / e. Axioms of PL
Predicate logic retains the axioms of propositional logic [Devlin]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / b. Axiom of Extensionality I
Extensionality: ∀x ∀y (∀z (z ∈ x ↔ z ∈ y) → x = y) [Kunen]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / c. Axiom of Pairing II
Pairing: ∀x ∀y ∃z (x ∈ z ∧ y ∈ z) [Kunen]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / d. Axiom of Unions III
Union: ∀F ∃A ∀Y ∀x (x ∈ Y ∧ Y ∈ F → x ∈ A) [Kunen]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / f. Axiom of Infinity V
Infinity: ∃x (0 ∈ x ∧ ∀y ∈ x (S(y) ∈ x) [Kunen]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / g. Axiom of Powers VI
Power Set: ∀x ∃y ∀z(z ⊂ x → z ∈ y) [Kunen]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / h. Axiom of Replacement VII
Replacement: ∀x∈A ∃!y φ(x,y) → ∃Y ∀X∈A ∃y∈Y φ(x,y) [Kunen]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / i. Axiom of Foundation VIII
Foundation:∀x(∃y(y∈x) → ∃y(y∈x ∧ ¬∃z(z∈x ∧ z∈y))) [Kunen]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX
Choice: ∀A ∃R (R well-orders A) [Kunen]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / k. Axiom of Existence
Set Existence: ∃x (x = x) [Kunen]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / n. Axiom of Comprehension
Comprehension: ∃y ∀x (x ∈ y ↔ x ∈ z ∧ φ) [Kunen]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / o. Axiom of Constructibility V = L
Constructibility: V = L (all sets are constructible) [Kunen]
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
Situation theory is logic that takes account of context [Devlin]
5. Theory of Logic / A. Overview of Logic / 2. History of Logic
Golden ages: 1900-1960 for pure logic, and 1950-1985 for applied logic [Devlin]
Montague's intensional logic incorporated the notion of meaning [Devlin]
5. Theory of Logic / B. Logical Consequence / 7. Strict Implication
Where a conditional is purely formal, an implication implies a link between premise and conclusion [Devlin]
5. Theory of Logic / E. Structures of Logic / 1. Logical Form
Sentences of apparent identical form can have different contextual meanings [Devlin]
5. Theory of Logic / L. Paradox / 4. Paradoxes in Logic / a. Achilles paradox
Space and time are atomic in the arrow, and divisible in the tortoise [Devlin]
8. Modes of Existence / A. Relations / 4. Formal Relations / b. Equivalence relation
An 'equivalence' relation is one which is reflexive, symmetric and transitive [Kunen]
13. Knowledge Criteria / D. Scepticism / 1. Scepticism
Anaxarchus said that he was not even sure that he knew nothing [Anaxarchus, by Diog. Laertius]
13. Knowledge Criteria / E. Relativism / 5. Language Relativism
People still say the Hopi have no time concepts, despite Whorf's later denial [Devlin]
19. Language / C. Assigning Meanings / 1. Syntax
How do we parse 'time flies like an arrow' and 'fruit flies like an apple'? [Devlin]
19. Language / D. Propositions / 2. Abstract Propositions / a. Propositions as sense
The distinction between sentences and abstract propositions is crucial in logic [Devlin]