Combining Texts

All the ideas for 'On the Question of Absolute Undecidability', 'Content Preservation' and 'The Language of Morals'

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9 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]
     Full Idea: There are many coherent stopping points in the hierarchy of increasingly strong mathematical systems, starting with strict finitism, and moving up through predicativism to the higher reaches of set theory.
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], Intro)
'Reflection principles' say the whole truth about sets can't be captured [Koellner]
     Full Idea: Roughly speaking, 'reflection principles' assert that anything true in V [the set hierarchy] falls short of characterising V in that it is true within some earlier level.
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], 2.1)
5. Theory of Logic / K. Features of Logics / 5. Incompleteness
We have no argument to show a statement is absolutely undecidable [Koellner]
     Full Idea: There is at present no solid argument to the effect that a given statement is absolutely undecidable.
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], 5.3)
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]
     Full Idea: Some of the standard large cardinals (in order of increasing (logical) strength) are: inaccessible, Mahlo, weakly compact, indescribable, Erdös, measurable, strong, Wodin, supercompact, huge etc. (...and ineffable).
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], 1.4)
     A reaction: [I don't understand how cardinals can have 'logical strength', but I pass it on anyway]
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]
     Full Idea: To the extent that we are justified in accepting Peano Arithmetic we are justified in accepting its consistency, and so we know how to expand the axiom system so as to overcome the limitation [of Gödel's Second Theorem].
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], 1.1)
     A reaction: Each expansion brings a limitation, but then you can expand again.
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]
     Full Idea: The arithmetical instances of undecidability that arise at one stage of the hierarchy are settled at the next.
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], 1.4)
7. Existence / C. Structure of Existence / 5. Supervenience / c. Significance of supervenience
The goodness of a picture supervenes on the picture; duplicates must be equally good [Hare]
     Full Idea: Characteristic of value-words is that they name 'supervenient' properties. If we are discussing whether a picture is a good picture, ..and there is another picture that is a replica of it, we cannot say 'they are alike, but one is good and the other not'.
     From: Richard M. Hare (The Language of Morals [1952], 5.2)
     A reaction: [compressed] Horgan says this is the passage which introduced 'supervenience' into contemporary discussions. I think the best simple word for it is that the goodness of the picture 'tracks' its physical characteristics. It also depend on them.
13. Knowledge Criteria / C. External Justification / 1. External Justification
Subjects may be unaware of their epistemic 'entitlements', unlike their 'justifications' [Burge]
     Full Idea: I call 'entitlement' (as opposed to justification) the epistemic rights or warrants that need not be understood by or even be accessible to the subject.
     From: Tyler Burge (Content Preservation [1993]), quoted by Paul Boghossian - Analyticity Reconsidered §III
     A reaction: I espouse a coherentism that has both internal and external components, and is mediated socially. In Burge's sense, animals will sometimes have 'entitlement'. I prefer, though, not to call this 'knowledge'. 'Entitled true belief' is good.
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / i. Prescriptivism
In primary evaluative words like 'ought' prescription is constant but description can vary [Hare, by Hooker,B]
     Full Idea: Hare says words are secondarily evaluative (e.g. 'soft-hearted') if prescriptive meaning varies but description is constant; primarily evaluative words ('good', 'right', 'ought') are the opposite, with the descriptive content varying.
     From: report of Richard M. Hare (The Language of Morals [1952]) by Brad W. Hooker - Prescriptivism p.640
     A reaction: I would have thought that the prescriptive meaning of the evaluative word could at least vary in strength. You really, really ought to do that.