Combining Texts

All the ideas for 'Why coherence is not enough', 'A Tour through Mathematical Logic' and 'works'

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32 ideas

1. Philosophy / E. Nature of Metaphysics / 3. Metaphysical Systems
21489 Super-ordinate disciplines give laws or principles; subordinate disciplines give concrete cases [Peirce, by Atkin]
3. Truth / E. Pragmatic Truth / 1. Pragmatic Truth
19095 Pragmatic 'truth' is a term to cover the many varied aims of enquiry [Peirce, by Misak]
19097 Peirce did not think a belief was true if it was useful [Peirce, by Misak]
21494 If truth is the end of enquiry, what if it never ends, or ends prematurely? [Atkin on Peirce]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / b. Terminology of PL
13520 A 'tautology' must include connectives [Wolf,RS]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / c. Derivation rules of PL
13524 Deduction Theorem: T∪{P}|-Q, then T|-(P→Q), which justifies Conditional Proof [Wolf,RS]
4. Formal Logic / C. Predicate Calculus PC / 2. Tools of Predicate Calculus / d. Universal quantifier ∀
13521 Universal Specification: ∀xP(x) implies P(t). True for all? Then true for an instance [Wolf,RS]
13522 Universal Generalization: If we prove P(x) with no special assumptions, we can conclude ∀xP(x) [Wolf,RS]
4. Formal Logic / C. Predicate Calculus PC / 2. Tools of Predicate Calculus / e. Existential quantifier ∃
13523 Existential Generalization (or 'proof by example'): if we can say P(t), then we can say something is P [Wolf,RS]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / e. Axiom of the Empty Set IV
13529 Empty Set: ∃x∀y ¬(y∈x). The unique empty set exists [Wolf,RS]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / n. Axiom of Comprehension
13526 Comprehension Axiom: if a collection is clearly specified, it is a set [Wolf,RS]
5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
13534 In first-order logic syntactic and semantic consequence (|- and |=) nicely coincide [Wolf,RS]
13535 First-order logic is weakly complete (valid sentences are provable); we can't prove every sentence or its negation [Wolf,RS]
5. Theory of Logic / C. Ontology of Logic / 3. If-Thenism
21493 Pure mathematics deals only with hypotheses, of which the reality does not matter [Peirce]
5. Theory of Logic / D. Assumptions for Logic / 1. Bivalence
19102 Bivalence is a regulative assumption of enquiry - not a law of logic [Peirce, by Misak]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
13519 Model theory uses sets to show that mathematical deduction fits mathematical truth [Wolf,RS]
13531 Model theory reveals the structures of mathematics [Wolf,RS]
13532 Model theory 'structures' have a 'universe', some 'relations', some 'functions', and some 'constants' [Wolf,RS]
13533 First-order model theory rests on completeness, compactness, and the Löwenheim-Skolem-Tarski theorem [Wolf,RS]
5. Theory of Logic / J. Model Theory in Logic / 2. Isomorphisms
13537 An 'isomorphism' is a bijection that preserves all structural components [Wolf,RS]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
13539 The LST Theorem is a serious limitation of first-order logic [Wolf,RS]
5. Theory of Logic / K. Features of Logics / 4. Completeness
13538 If a theory is complete, only a more powerful language can strengthen it [Wolf,RS]
5. Theory of Logic / K. Features of Logics / 10. Monotonicity
13525 Most deductive logic (unlike ordinary reasoning) is 'monotonic' - we don't retract after new givens [Wolf,RS]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
13530 An ordinal is an equivalence class of well-orderings, or a transitive set whose members are transitive [Wolf,RS]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
13518 Modern mathematics has unified all of its objects within set theory [Wolf,RS]
7. Existence / D. Theories of Reality / 3. Reality
10352 The real is the idea in which the community ultimately settles down [Peirce]
8. Modes of Existence / A. Relations / 1. Nature of Relations
13498 Peirce and others began the mapping out of relations [Peirce, by Hart,WD]
8. Modes of Existence / C. Powers and Dispositions / 6. Dispositions / d. Dispositions as occurrent
21491 Peirce's later realism about possibilities and generalities went beyond logical positivism [Peirce, by Atkin]
10. Modality / E. Possible worlds / 1. Possible Worlds / d. Possible worlds actualism
16376 The possible can only be general, and the force of actuality is needed to produce a particular [Peirce]
11. Knowledge Aims / B. Certain Knowledge / 3. Fallibilism
19107 Inquiry is not standing on bedrock facts, but standing in hope on a shifting bog [Peirce]
13. Knowledge Criteria / A. Justification Problems / 2. Justification Challenges / a. Agrippa's trilemma
8840 There are five possible responses to the problem of infinite regress in justification [Cleve]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / a. Foundationalism
8841 Modern foundationalists say basic beliefs are fallible, and coherence is relevant [Cleve]