Combining Texts

All the ideas for 'On the Question of Absolute Undecidability', 'Identity and Necessity' and 'On Second-Order Logic'

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21 ideas

4. Formal Logic / F. Set Theory ST / 1. Set Theory
17884 Mathematical set theory has many plausible stopping points, such as finitism, and predicativism [Koellner]
17893 'Reflection principles' say the whole truth about sets can't be captured [Koellner]
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
14249 Boolos reinterprets second-order logic as plural logic [Boolos, by Oliver/Smiley]
10830 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
10829 A sentence can't be a truth of logic if it asserts the existence of certain sets [Boolos]
5. Theory of Logic / F. Referring in Logic / 1. Naming / b. Names as descriptive
9175 We may fix the reference of 'Cicero' by a description, but thereafter the name is rigid [Kripke]
5. Theory of Logic / F. Referring in Logic / 1. Naming / c. Names as referential
9171 The function of names is simply to refer [Kripke]
5. Theory of Logic / G. Quantification / 2. Domain of Quantification
10832 '∀x x=x' only means 'everything is identical to itself' if the range of 'everything' is fixed [Boolos]
5. Theory of Logic / K. Features of Logics / 4. Completeness
10834 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 / 5. Incompleteness
17894 We have no argument to show a statement is absolutely undecidable [Koellner]
5. Theory of Logic / K. Features of Logics / 6. Compactness
13841 Why should compactness be definitive of logic? [Boolos, by Hacking]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / i. Cardinal infinity
17890 There are at least eleven types of large cardinal, of increasing logical strength [Koellner]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / d. Peano arithmetic
17887 PA is consistent as far as we can accept, and we expand axioms to overcome limitations [Koellner]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / e. Peano arithmetic 2nd-order
10833 Many concepts can only be expressed by second-order logic [Boolos]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / g. Incompleteness of Arithmetic
17891 Arithmetical undecidability is always settled at the next stage up [Koellner]
10. Modality / D. Knowledge of Modality / 3. A Posteriori Necessary
9174 It is necessary that this table is not made of ice, but we don't know it a priori [Kripke]
10. Modality / E. Possible worlds / 3. Transworld Objects / b. Rigid designation
9172 A 'rigid designator' designates the same object in all possible worlds [Kripke]
9173 We cannot say that Nixon might have been a different man from the one he actually was [Kripke]
10. Modality / E. Possible worlds / 3. Transworld Objects / c. Counterparts
9176 Modal statements about this table never refer to counterparts; that confuses epistemology and metaphysics [Kripke]
17. Mind and Body / A. Mind-Body Dualism / 7. Zombies
9177 Identity theorists must deny that pains can be imagined without brain states [Kripke]
17. Mind and Body / E. Mind as Physical / 7. Anti-Physicalism / e. Modal argument
9178 Pain, unlike heat, is picked out by an essential property [Kripke]