Combining Texts

All the ideas for 'On the Question of Absolute Undecidability', 'Summula philosophiae naturalis' and 'Conditionals'

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18 ideas

4. Formal Logic / F. Set Theory ST / 1. Set Theory
Mathematical set theory has many plausible stopping points, such as finitism, and predicativism [Koellner]
'Reflection principles' say the whole truth about sets can't be captured [Koellner]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
'¬', '&', and 'v' are truth functions: the truth of the compound is fixed by the truth of the components [Jackson]
5. Theory of Logic / K. Features of Logics / 5. Incompleteness
We have no argument to show a statement is absolutely undecidable [Koellner]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / i. Cardinal infinity
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
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 / g. Incompleteness of Arithmetic
Arithmetical undecidability is always settled at the next stage up [Koellner]
7. Existence / E. Categories / 5. Category Anti-Realism
Ockham was an anti-realist about the categories [William of Ockham, by Pasnau]
9. Objects / C. Structure of Objects / 4. Quantity of an Object
Ockham says matter must be extended, so we don't need Quantity [William of Ockham, by Pasnau]
Matter gets its quantity from condensation and rarefaction, which is just local motion [William of Ockham]
10. Modality / B. Possibility / 8. Conditionals / b. Types of conditional
Possible worlds for subjunctives (and dispositions), and no-truth for indicatives? [Jackson]
10. Modality / B. Possibility / 8. Conditionals / c. Truth-function conditionals
Modus ponens requires that A→B is F when A is T and B is F [Jackson]
When A and B have the same truth value, A→B is true, because A→A is a logical truth [Jackson]
(A&B)→A is a logical truth, even if antecedent false and consequent true, so it is T if A is F and B is T [Jackson]
10. Modality / B. Possibility / 8. Conditionals / d. Non-truthfunction conditionals
In the possible worlds account of conditionals, modus ponens and modus tollens are validated [Jackson]
Only assertions have truth-values, and conditionals are not proper assertions [Jackson]
Possible worlds account, unlike A⊃B, says nothing about when A is false [Jackson]
10. Modality / B. Possibility / 8. Conditionals / f. Pragmatics of conditionals
We can't insist that A is relevant to B, as conditionals can express lack of relevance [Jackson]