Combining Texts

All the ideas for 'fragments/reports', 'Introduction to the Theory of Logic' and 'The Analects (Lunyu)'

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28 ideas

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 |=
10893 Γ |= φ for sentences if φ is true when all of Γ is true [Zalabardo]
10899 Γ |= φ if φ is true when all of Γ is true, for all structures and interpretations [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]
19. Language / F. Communication / 1. Rhetoric
7357 People who control others with fluent language often end up being hated [Kongzi (Confucius)]
22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / h. Against ethics
7358 All men prefer outward appearance to true excellence [Kongzi (Confucius)]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / e. Human nature
7362 Humans are similar, but social conventions drive us apart (sages and idiots being the exceptions) [Kongzi (Confucius)]
23. Ethics / B. Contract Ethics / 2. Golden Rule
7360 Do not do to others what you would not desire yourself [Kongzi (Confucius)]
23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / f. The Mean
7359 Excess and deficiency are equally at fault [Kongzi (Confucius)]
23. Ethics / C. Virtue Theory / 3. Virtues / a. Virtues
7363 The virtues of the best people are humility, maganimity, sincerity, diligence, and graciousness [Kongzi (Confucius)]
24. Political Theory / C. Ruling a State / 2. Leaders / d. Elites
7361 Men of the highest calibre avoid political life completely [Kongzi (Confucius)]
24. Political Theory / D. Ideologies / 3. Conservatism
23393 Confucianism assumes that all good developments have happened, and there is only one Way [Norden on Kongzi (Confucius)]
26. Natural Theory / A. Speculations on Nature / 5. Infinite in Nature
1748 Archelaus was the first person to say that the universe is boundless [Archelaus, by Diog. Laertius]
27. Natural Reality / G. Biology / 3. Evolution
5989 Archelaus said life began in a primeval slime [Archelaus, by Schofield]