Combining Texts

All the ideas for 'Demonstratives', 'Causal and Metaphysical Necessity' and 'On Second-Order Logic'

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19 ideas

5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
Boolos reinterprets second-order logic as plural logic [Boolos, by Oliver/Smiley]
Second-order logic metatheory is set-theoretic, and second-order validity has set-theoretic problems [Boolos]
5. Theory of Logic / C. Ontology of Logic / 1. Ontology of Logic
A sentence can't be a truth of logic if it asserts the existence of certain sets [Boolos]
5. Theory of Logic / G. Quantification / 2. Domain of Quantification
'∀x x=x' only means 'everything is identical to itself' if the range of 'everything' is fixed [Boolos]
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
Restrict 'logical truth' to formal logic, rather than including analytic and metaphysical truths [Shoemaker]
5. Theory of Logic / K. Features of Logics / 4. Completeness
Weak completeness: if it is valid, it is provable. Strong: it is provable from a set of sentences [Boolos]
5. Theory of Logic / K. Features of Logics / 6. Compactness
Why should compactness be definitive of logic? [Boolos, by Hacking]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / e. Peano arithmetic 2nd-order
Many concepts can only be expressed by second-order logic [Boolos]
8. Modes of Existence / B. Properties / 1. Nature of Properties
A property's causal features are essential, and only they fix its identity [Shoemaker]
I claim that a property has its causal features in all possible worlds [Shoemaker]
8. Modes of Existence / C. Powers and Dispositions / 3. Powers as Derived
I now deny that properties are cluster of powers, and take causal properties as basic [Shoemaker]
10. Modality / A. Necessity / 5. Metaphysical Necessity
If something is possible, but not nomologically possible, we need metaphysical possibility [Shoemaker]
10. Modality / D. Knowledge of Modality / 1. A Priori Necessary
Once you give up necessity as a priori, causal necessity becomes the main type of necessity [Shoemaker]
10. Modality / D. Knowledge of Modality / 4. Conceivable as Possible / a. Conceivable as possible
Empirical evidence shows that imagining a phenomenon can show it is possible [Shoemaker]
Imagination reveals conceptual possibility, where descriptions avoid contradiction or incoherence [Shoemaker]
14. Science / C. Induction / 5. Paradoxes of Induction / a. Grue problem
'Grue' only has causal features because of its relation to green [Shoemaker]
19. Language / C. Assigning Meanings / 10. Two-Dimensional Semantics
Indexicals have a 'character' (the standing meaning), and a 'content' (truth-conditions for one context) [Kaplan, by Macià/Garcia-Carpentiro]
'Content' gives the standard modal profile, and 'character' gives rules for a context [Kaplan, by Schroeter]
26. Natural Theory / D. Laws of Nature / 5. Laws from Universals
We might say laws are necessary by combining causal properties with Armstrong-Dretske-Tooley laws [Shoemaker]