Combining Texts

All the ideas for 'Logical Pluralism', 'Practical Necessity' and 'Set Theory'

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35 ideas

3. Truth / A. Truth Problems / 1. Truth
13252 Some truths have true negations [Beall/Restall]
3. Truth / B. Truthmakers / 5. What Makes Truths / b. Objects make truths
13247 A truthmaker is an object which entails a sentence [Beall/Restall]
4. Formal Logic / E. Nonclassical Logics / 2. Intuitionist Logic
13249 (∀x)(A v B) |- (∀x)A v (∃x)B) is valid in classical logic but invalid intuitionistically [Beall/Restall]
4. Formal Logic / E. Nonclassical Logics / 5. Relevant Logic
13243 Excluded middle must be true for some situation, not for all situations [Beall/Restall]
13242 It's 'relevantly' valid if all those situations make it true [Beall/Restall]
13246 Relevant logic does not abandon classical logic [Beall/Restall]
13245 Relevant consequence says invalidity is the conclusion not being 'in' the premises [Beall/Restall]
13254 A doesn't imply A - that would be circular [Beall/Restall]
13255 Relevant logic may reject transitivity [Beall/Restall]
4. Formal Logic / E. Nonclassical Logics / 6. Free Logic
13250 Free logic terms aren't existential; classical is non-empty, with referring names [Beall/Restall]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / b. Axiom of Extensionality I
13030 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
13032 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
13033 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
13037 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
13038 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
13034 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
13039 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
13036 Choice: ∀A ∃R (R well-orders A) [Kunen]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / k. Axiom of Existence
13029 Set Existence: ∃x (x = x) [Kunen]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / n. Axiom of Comprehension
13031 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
13040 Constructibility: V = L (all sets are constructible) [Kunen]
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
13235 Logic studies consequence; logical truths are consequences of everything, or nothing [Beall/Restall]
13238 Syllogisms are only logic when they use variables, and not concrete terms [Beall/Restall]
5. Theory of Logic / A. Overview of Logic / 2. History of Logic
13234 The view of logic as knowing a body of truths looks out-of-date [Beall/Restall]
5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
13232 Logic studies arguments, not formal languages; this involves interpretations [Beall/Restall]
5. Theory of Logic / A. Overview of Logic / 8. Logic of Mathematics
13241 The model theory of classical predicate logic is mathematics [Beall/Restall]
5. Theory of Logic / B. Logical Consequence / 2. Types of Consequence
13253 There are several different consequence relations [Beall/Restall]
5. Theory of Logic / B. Logical Consequence / 4. Semantic Consequence |=
13240 A sentence follows from others if they always model it [Beall/Restall]
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
13236 Logical truth is much more important if mathematics rests on it, as logicism claims [Beall/Restall]
5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / d. The Preface paradox
13237 Preface Paradox affirms and denies the conjunction of propositions in the book [Beall/Restall]
10. Modality / A. Necessity / 3. Types of Necessity
13244 Relevant necessity is always true for some situation (not all situations) [Beall/Restall]
10. Modality / A. Necessity / 10. Impossibility
23283 Necessity implies possibility, but in experience it matters which comes first [Williams,B]
18. Thought / A. Modes of Thought / 6. Judgement / a. Nature of Judgement
13239 Judgement is always predicating a property of a subject [Beall/Restall]
19. Language / C. Assigning Meanings / 8. Possible Worlds Semantics
13248 We can rest truth-conditions on situations, rather than on possible worlds [Beall/Restall]
19. Language / D. Propositions / 1. Propositions
13233 Propositions commit to content, and not to any way of spelling it out [Beall/Restall]