Combining Texts

All the ideas for 'Classical Cosmology (frags)', 'Introduction to the Theory of Logic' and 'Lives of Eminent Philosophers'

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26 ideas

2. Reason / C. Styles of Reason / 1. Dialectic
3035 Dialectic involves conversations with short questions and brief answers [Diog. Laertius]
4. Formal Logic / F. Set Theory ST / 1. Set Theory
10888 Sets can be defined by 'enumeration', or by 'abstraction' (based on a property) [Zalabardo]
4. Formal Logic / F. Set Theory ST / 2. Mechanics of Set Theory / b. Terminology of ST
10889 The 'Cartesian Product' of two sets relates them by pairing every element with every element [Zalabardo]
10890 A 'partial ordering' is reflexive, antisymmetric and transitive [Zalabardo]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
10886 Determinacy: an object is either in a set, or it isn't [Zalabardo]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / l. Axiom of Specification
10887 Specification: Determinate totals of objects always make a set [Zalabardo]
5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
10897 A first-order 'sentence' is a formula with no free variables [Zalabardo]
5. Theory of Logic / B. Logical Consequence / 4. Semantic Consequence |=
10899 Γ |= φ if φ is true when all of Γ is true, for all structures and interpretations [Zalabardo]
10893 Γ |= φ for sentences if φ is true when all of Γ is true [Zalabardo]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / b. Basic connectives
10896 Propositional logic just needs ¬, and one of ∧, ∨ and → [Zalabardo]
5. Theory of Logic / I. Semantics of Logic / 1. Semantics of Logic
10898 The semantics shows how truth values depend on instantiations of properties and relations [Zalabardo]
10902 We can do semantics by looking at given propositions, or by building new ones [Zalabardo]
5. Theory of Logic / I. Semantics of Logic / 2. Formal Truth
10892 We make a truth assignment to T and F, which may be true and false, but merely differ from one another [Zalabardo]
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
10895 'Logically true' (|= φ) is true for every truth-assignment [Zalabardo]
10900 Logically true sentences are true in all structures [Zalabardo]
5. Theory of Logic / I. Semantics of Logic / 4. Satisfaction
10894 A sentence-set is 'satisfiable' if at least one truth-assignment makes them all true [Zalabardo]
10901 Some formulas are 'satisfiable' if there is a structure and interpretation that makes them true [Zalabardo]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
10903 A structure models a sentence if it is true in the model, and a set of sentences if they are all true in the model [Zalabardo]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / f. Mathematical induction
10891 If a set is defined by induction, then proof by induction can be applied to it [Zalabardo]
13. Knowledge Criteria / A. Justification Problems / 2. Justification Challenges / a. Agrippa's trilemma
1816 Sceptics say demonstration depends on self-demonstrating things, or indemonstrable things [Diog. Laertius]
13. Knowledge Criteria / D. Scepticism / 1. Scepticism
1819 Scepticism has two dogmas: that nothing is definable, and every argument has an opposite argument [Diog. Laertius]
13. Knowledge Criteria / D. Scepticism / 6. Scepticism Critique
3064 When sceptics say that nothing is definable, or all arguments have an opposite, they are being dogmatic [Diog. Laertius]
14. Science / C. Induction / 4. Reason in Induction
3033 Induction moves from some truths to similar ones, by contraries or consequents [Diog. Laertius]
22. Metaethics / C. The Good / 3. Pleasure / b. Types of pleasure
1838 Cyrenaic pleasure is a motion, but Epicurean pleasure is a condition [Diog. Laertius]
23. Ethics / A. Egoism / 1. Ethical Egoism
1769 Cynics believe that when a man wishes for nothing he is like the gods [Diog. Laertius]
27. Natural Reality / E. Cosmology / 1. Cosmology
5994 Is the cosmos open or closed, mechanical or teleological, alive or inanimate, and created or eternal? [Robinson,TM, by PG]