Combining Texts

All the ideas for 'Logical Consequence', 'fragments/reports' and 'The Nature of Necessity'

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17 ideas

4. Formal Logic / A. Syllogistic Logic / 2. Syllogistic Logic
10688 'Equivocation' is when terms do not mean the same thing in premises and conclusion [Beall/Restall]
5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
10690 Formal logic is invariant under permutations, or devoid of content, or gives the norms for thought [Beall/Restall]
5. Theory of Logic / B. Logical Consequence / 2. Types of Consequence
10691 Logical consequence needs either proofs, or absence of counterexamples [Beall/Restall]
5. Theory of Logic / B. Logical Consequence / 4. Semantic Consequence |=
10695 Logical consequence is either necessary truth preservation, or preservation based on interpretation [Beall/Restall]
5. Theory of Logic / B. Logical Consequence / 8. Material Implication
10689 A step is a 'material consequence' if we need contents as well as form [Beall/Restall]
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
10696 A 'logical truth' (or 'tautology', or 'theorem') follows from empty premises [Beall/Restall]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
10693 Models are mathematical structures which interpret the non-logical primitives [Beall/Restall]
6. Mathematics / B. Foundations for Mathematics / 2. Proof in Mathematics
10692 Hilbert proofs have simple rules and complex axioms, and natural deduction is the opposite [Beall/Restall]
10. Modality / E. Possible worlds / 1. Possible Worlds / d. Possible worlds actualism
18383 Plantinga says there is just this world, with possibilities expressed in propositions [Plantinga, by Armstrong]
10. Modality / E. Possible worlds / 3. Transworld Objects / b. Rigid designation
11891 Possibilities for an individual can only refer to that individual, in some possible world [Plantinga, by Mackie,P]
13. Knowledge Criteria / D. Scepticism / 1. Scepticism
411 If we succeed in speaking the truth, we cannot know we have done it [Xenophanes]
13. Knowledge Criteria / E. Relativism / 1. Relativism
412 If God had not created honey, men would say figs are sweeter [Xenophanes]
26. Natural Theory / A. Speculations on Nature / 6. Early Matter Theories / e. The One
1640 The basic Eleatic belief was that all things are one [Xenophanes, by Plato]
28. God / A. Divine Nature / 2. Divine Nature
3055 Xenophanes said the essence of God was spherical and utterly inhuman [Xenophanes, by Diog. Laertius]
28. God / B. Proving God / 2. Proofs of Reason / a. Ontological Proof
20704 A possible world contains a being of maximal greatness - which is existence in all worlds [Plantinga, by Davies,B]
28. God / C. Attitudes to God / 5. Atheism
407 Mortals believe gods are born, and have voices and clothes just like mortals [Xenophanes]
408 Ethiopian gods have black hair, and Thracian gods have red hair [Xenophanes]