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All the ideas for 'Academica', 'A Tour through Mathematical Logic' and 'A Study of Concepts'

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39 ideas

2. Reason / C. Styles of Reason / 1. Dialectic
Dialectic is speech cast in the form of logical argument [Cicero]
2. Reason / D. Definition / 13. Against Definition
Most people can't even define a chair [Peacocke]
3. Truth / A. Truth Problems / 1. Truth
There cannot be more than one truth [Cicero]
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 Generalization: If we prove P(x) with no special assumptions, we can conclude ∀xP(x) [Wolf,RS]
Universal Specification: ∀xP(x) implies P(t). True for all? Then true for an instance [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 / D. Assumptions for Logic / 2. Excluded Middle
Dialectic assumes that all statements are either true or false, but self-referential paradoxes are a big problem [Cicero]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
Model theory reveals the structures of mathematics [Wolf,RS]
Model theory 'structures' have a 'universe', some 'relations', some 'functions', and some 'constants' [Wolf,RS]
Model theory uses sets to show that mathematical deduction fits mathematical truth [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]
12. Knowledge Sources / B. Perception / 1. Perception
If we have complete healthy senses, what more could the gods give us? [Cicero]
Perceptual concepts causally influence the content of our experiences [Peacocke]
12. Knowledge Sources / B. Perception / 6. Inference in Perception
Perception has proto-propositions, between immediate experience and concepts [Peacocke]
12. Knowledge Sources / E. Direct Knowledge / 4. Memory
How can there be a memory of what is false? [Cicero]
13. Knowledge Criteria / D. Scepticism / 3. Illusion Scepticism
Every true presentation can have a false one of the same quality [Cicero]
15. Nature of Minds / B. Features of Minds / 1. Consciousness / f. Higher-order thought
Consciousness of a belief isn't a belief that one has it [Peacocke]
18. Thought / D. Concepts / 1. Concepts / b. Concepts in philosophy
Philosophy should merely give necessary and sufficient conditions for concept possession [Peacocke, by Machery]
Peacocke's account of possession of a concept depends on one view of counterfactuals [Peacocke, by Machery]
Peacocke's account separates psychology from philosophy, and is very sketchy [Machery on Peacocke]
18. Thought / D. Concepts / 3. Ontology of Concepts / b. Concepts as abilities
Possessing a concept is being able to make judgements which use it [Peacocke]
A concept is just what it is to possess that concept [Peacocke]
Employing a concept isn't decided by introspection, but by making judgements using it [Peacocke]
18. Thought / D. Concepts / 4. Structure of Concepts / b. Analysis of concepts
An analysis of concepts must link them to something unconceptualized [Peacocke]
18. Thought / D. Concepts / 4. Structure of Concepts / f. Theory theory of concepts
Concepts are constituted by their role in a group of propositions to which we are committed [Peacocke, by Greco]
19. Language / B. Reference / 1. Reference theories
A concept's reference is what makes true the beliefs of its possession conditions [Peacocke, by Horwich]
23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / c. Motivation for virtue
Virtues must be very detached, to avoid being motivated by pleasure [Cicero]