Combining Texts

All the ideas for 'Quodlibeta', 'The Logical Syntax of Language' and 'Modality'

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23 ideas

2. Reason / A. Nature of Reason / 1. On Reason
5750 Consistency is modal, saying propositions are consistent if they could be true together [Melia]
4. Formal Logic / C. Predicate Calculus PC / 1. Predicate Calculus PC
5737 Predicate logic has connectives, quantifiers, variables, predicates, equality, names and brackets [Melia]
4. Formal Logic / D. Modal Logic ML / 1. Modal Logic
5744 First-order predicate calculus is extensional logic, but quantified modal logic is intensional (hence dubious) [Melia]
5. Theory of Logic / B. Logical Consequence / 1. Logical Consequence
13342 Carnap defined consequence by contradiction, but this is unintuitive and changes with substitution [Tarski on Carnap]
5. Theory of Logic / C. Ontology of Logic / 4. Logic by Convention
13251 Each person is free to build their own logic, just by specifying a syntax [Carnap]
5. Theory of Logic / G. Quantification / 5. Second-Order Quantification
5740 Second-order logic needs second-order variables and quantification into predicate position [Melia]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
5741 If every model that makes premises true also makes conclusion true, the argument is valid [Melia]
7. Existence / D. Theories of Reality / 8. Facts / a. Facts
5736 No sort of plain language or levels of logic can express modal facts properly [Melia]
5735 Maybe names and predicates can capture any fact [Melia]
7. Existence / E. Categories / 3. Proposed Categories
16657 Substance, Quantity and Quality are real; other categories depend on those three [Henry of Ghent]
8. Modes of Existence / A. Relations / 1. Nature of Relations
16658 The only reality in the category of Relation is things from another category [Henry of Ghent]
8. Modes of Existence / B. Properties / 8. Properties as Modes
16645 Accidents are diminished beings, because they are dispositions of substance (unqualified being) [Henry of Ghent]
9. Objects / F. Identity among Objects / 7. Indiscernible Objects
5746 The Identity of Indiscernibles is contentious for qualities, and trivial for non-qualities [Melia]
10. Modality / A. Necessity / 2. Nature of Necessity
5738 We may be sure that P is necessary, but is it necessarily necessary? [Melia]
10. Modality / A. Necessity / 4. De re / De dicto modality
5732 'De re' modality is about things themselves, 'de dicto' modality is about propositions [Melia]
10. Modality / B. Possibility / 1. Possibility
5739 Sometimes we want to specify in what ways a thing is possible [Melia]
10. Modality / E. Possible worlds / 1. Possible Worlds / a. Possible worlds
5734 Possible worlds make it possible to define necessity and counterfactuals without new primitives [Melia]
5742 In possible worlds semantics the modal operators are treated as quantifiers [Melia]
5743 If possible worlds semantics is not realist about possible worlds, logic becomes merely formal [Melia]
5749 Possible worlds could be real as mathematics, propositions, properties, or like books [Melia]
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / b. Worlds as fictions
5751 The truth of propositions at possible worlds are implied by the world, just as in books [Melia]
11. Knowledge Aims / C. Knowing Reality / 3. Idealism / b. Transcendental idealism
22012 Kant says things-in-themselves cause sensations, but then makes causation transcendental! [Henry of Ghent, by Pinkard]
19. Language / A. Nature of Meaning / 5. Meaning as Verification
5748 We accept unverifiable propositions because of simplicity, utility, explanation and plausibility [Melia]