Combining Texts

All the ideas for 'Elements of Mathematical Logic', 'First-Order Logic' and 'Introduction to the Philosophy of History'

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17 ideas

1. Philosophy / C. History of Philosophy / 4. Later European Philosophy / d. Nineteenth century philosophy
20109 Hegel inserted society and history between the God-world, man-nature, man-being binary pairs [Hegel, by Safranski]
4. Formal Logic / E. Nonclassical Logics / 3. Many-Valued Logic
8942 Lukasiewicz's L3 logic has three truth-values, T, F and I (for 'indeterminate') [Lukasiewicz, by Fisher]
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
10282 Logic is the study of sound argument, or of certain artificial languages (or applying the latter to the former) [Hodges,W]
5. Theory of Logic / I. Semantics of Logic / 1. Semantics of Logic
10283 A formula needs an 'interpretation' of its constants, and a 'valuation' of its variables [Hodges,W]
10284 There are three different standard presentations of semantics [Hodges,W]
10285 I |= φ means that the formula φ is true in the interpretation I [Hodges,W]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
10289 Up Löwenheim-Skolem: if infinite models, then arbitrarily large models [Hodges,W]
10288 Down Löwenheim-Skolem: if a countable language has a consistent theory, that has a countable model [Hodges,W]
5. Theory of Logic / K. Features of Logics / 6. Compactness
10287 If a first-order theory entails a sentence, there is a finite subset of the theory which entails it [Hodges,W]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
10286 A 'set' is a mathematically well-behaved class [Hodges,W]
22. Metaethics / C. The Good / 2. Happiness / a. Nature of happiness
23274 World history has no room for happiness [Hegel]
24. Political Theory / A. Basis of a State / 1. A People / b. The natural life
23275 The state of nature is one of untamed brutality [Hegel]
24. Political Theory / A. Basis of a State / 1. A People / c. A unified people
23276 The soul of the people is an organisation of its members which produces an essential unity [Hegel]
24. Political Theory / D. Ideologies / 6. Liberalism / g. Liberalism critique
23272 The human race matters, and individuals have little importance [Hegel]
24. Political Theory / D. Ideologies / 14. Nationalism
23273 In a good state the goal of the citizens and of the whole state are united [Hegel]
25. Social Practice / A. Freedoms / 5. Freedom of lifestyle
23271 The goal of the world is Spirit's consciousness and enactment of freedom [Hegel]
25. Social Practice / E. Policies / 5. Education / d. Study of history
23270 We should all agree that there is reason in history [Hegel]