Combining Texts

All the ideas for 'Saundaranandakavya', 'First-Order Logic' and 'Philosophy of Nature (Encylopedia II)'

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13 ideas

1. Philosophy / D. Nature of Philosophy / 2. Invocation to Philosophy
Pursue truth with the urgency of someone whose clothes are on fire [Ashvaghosha]
1. Philosophy / E. Nature of Metaphysics / 6. Metaphysics as Conceptual
Metaphysics is the lattice which makes incoming material intelligible [Hegel]
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
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
A formula needs an 'interpretation' of its constants, and a 'valuation' of its variables [Hodges,W]
There are three different standard presentations of semantics [Hodges,W]
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
Down Löwenheim-Skolem: if a countable language has a consistent theory, that has a countable model [Hodges,W]
Up Löwenheim-Skolem: if infinite models, then arbitrarily large models [Hodges,W]
5. Theory of Logic / K. Features of Logics / 6. Compactness
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
A 'set' is a mathematically well-behaved class [Hodges,W]
24. Political Theory / C. Ruling a State / 4. Changing the State / c. Revolution
All revolutions result from spirit changing its categories, to achieve a deeper understanding [Hegel]
29. Religion / C. Spiritual Disciplines / 3. Buddhism
The Eightfold Path concerns morality, wisdom, and tranquillity [Ashvaghosha]
29. Religion / D. Religious Issues / 2. Immortality / d. Heaven
At the end of a saint, he is not located in space, but just ceases to be disturbed [Ashvaghosha]