Combining Texts

All the ideas for 'The Nature of Things', 'Possible Worlds' and 'Gentzen's Analysis of First-Order Proofs'

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12 ideas

4. Formal Logic / F. Set Theory ST / 7. Natural Sets
9406 A class is natural when everybody can spot further members of it [Quinton]
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
13831 Logic is based on transitions between sentences [Prawitz]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
13825 Natural deduction introduction rules may represent 'definitions' of logical connectives [Prawitz]
5. Theory of Logic / H. Proof Systems / 4. Natural Deduction
13823 In natural deduction, inferences are atomic steps involving just one logical constant [Prawitz]
7. Existence / A. Nature of Existence / 2. Types of Existence
15789 Lewis's distinction of 'existing' from 'being actual' is Meinong's between 'existing' and 'subsisting' [Lycan on Lewis]
7. Existence / E. Categories / 5. Category Anti-Realism
15730 Extreme nominalists say all classification is arbitrary convention [Quinton]
8. Modes of Existence / B. Properties / 5. Natural Properties
15728 The naturalness of a class depends as much on the observers as on the objects [Quinton]
9407 Properties imply natural classes which can be picked out by everybody [Quinton]
8. Modes of Existence / D. Universals / 4. Uninstantiated Universals
15729 Uninstantiated properties must be defined using the instantiated ones [Quinton]
9. Objects / A. Existence of Objects / 5. Individuation / b. Individuation by properties
8520 An individual is a union of a group of qualities and a position [Quinton, by Campbell,K]
10. Modality / E. Possible worlds / 1. Possible Worlds / d. Possible worlds actualism
15790 Lewis can't know possible worlds without first knowing what is possible or impossible [Lycan on Lewis]
15791 What are the ontological grounds for grouping possibilia into worlds? [Lycan on Lewis]