Combining Texts

All the ideas for 'works', 'First-Order Logic' and 'Subjective and Objective'

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15 ideas

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
10288 Down Löwenheim-Skolem: if a countable language has a consistent theory, that has a countable model [Hodges,W]
10289 Up Löwenheim-Skolem: if infinite models, then arbitrarily large models [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]
12. Knowledge Sources / B. Perception / 4. Sense Data / d. Sense-data problems
3296 Sense-data are a false objectification of what is essentially subjective [Nagel]
15. Nature of Minds / A. Nature of Mind / 1. Mind / a. Mind
3295 Inner v outer brings astonishment that we are a particular person [Nagel]
16. Persons / B. Nature of the Self / 4. Presupposition of Self
3293 If you assert that we have an ego, you can still ask if that future ego will be me [Nagel]
16. Persons / F. Free Will / 1. Nature of Free Will
3292 The most difficult problem of free will is saying what the problem is [Nagel]
23. Ethics / D. Deontological Ethics / 3. Universalisability
3294 As far as possible we should become instruments to realise what is best from an eternal point of view [Nagel]
29. Religion / B. Monotheistic Religion / 4. Christianity / d. Heresy
16713 Philosophers are the forefathers of heretics [Tertullian]
29. Religion / D. Religious Issues / 1. Religious Commitment / e. Fideism
6610 I believe because it is absurd [Tertullian]