Combining Philosophers

All the ideas for Giordano Bruno, Robert S. Wolf and Paul Thagard

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33 ideas

2. Reason / A. Nature of Reason / 6. Coherence
Coherence problems have positive and negative restraints; solutions maximise constraint satisfaction [Thagard]
Coherence is explanatory, deductive, conceptual, analogical, perceptual, and deliberative [Thagard]
Explanatory coherence needs symmetry,explanation,analogy,data priority, contradiction,competition,acceptance [Thagard]
3. Truth / A. Truth Problems / 6. Verisimilitude
Verisimilitude comes from including more phenomena, and revealing what underlies [Thagard]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / b. Terminology of PL
A 'tautology' must include connectives [Wolf,RS]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / c. Derivation rules of PL
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 ∀
Universal Specification: ∀xP(x) implies P(t). True for all? Then true for an instance [Wolf,RS]
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 ∃
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
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
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
In first-order logic syntactic and semantic consequence (|- and |=) nicely coincide [Wolf,RS]
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 / J. Model Theory in Logic / 1. Logical Models
Model theory uses sets to show that mathematical deduction fits mathematical truth [Wolf,RS]
Model theory reveals the structures of mathematics [Wolf,RS]
Model theory 'structures' have a 'universe', some 'relations', some 'functions', and some 'constants' [Wolf,RS]
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
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
The LST Theorem is a serious limitation of first-order logic [Wolf,RS]
5. Theory of Logic / K. Features of Logics / 4. Completeness
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
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
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
Modern mathematics has unified all of its objects within set theory [Wolf,RS]
14. Science / B. Scientific Theories / 1. Scientific Theory
Neither a priori rationalism nor sense data empiricism account for scientific knowledge [Thagard]
14. Science / C. Induction / 6. Bayes's Theorem
Bayesian inference is forced to rely on approximations [Thagard]
14. Science / D. Explanation / 2. Types of Explanation / c. Explanations by coherence
3: If an analogous pair explain another analogous pair, then they all cohere [Thagard, by Smart]
1: Coherence is a symmetrical relation between two propositions [Thagard, by Smart]
4: For coherence, observation reports have a degree of intrinsic acceptability [Thagard, by Smart]
5: Contradictory propositions incohere [Thagard, by Smart]
6: A proposition's acceptability depends on its coherence with a system [Thagard, by Smart]
2: An explanation must wholly cohere internally, and with the new fact [Thagard, by Smart]
14. Science / D. Explanation / 3. Best Explanation / a. Best explanation
The best theory has the highest subjective (Bayesian) probability? [Thagard]
29. Religion / A. Polytheistic Religion / 2. Greek Polytheism
Bruno said that ancient Egyptian magic was the true religion [Bruno, by Yates]