Combining Texts

All the ideas for 'On the Question of Absolute Undecidability', 'The Birth of Tragedy' and 'How to Russell a Frege-Church'

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11 ideas

1. Philosophy / D. Nature of Philosophy / 1. Philosophy
Philosophy begins in the horror and absurdity of existence [Nietzsche, by Ansell Pearson]
     Full Idea: For Nietzsche philosophy begins in horror - existence is something both horrible and absurd.
     From: report of Friedrich Nietzsche (The Birth of Tragedy [1871]) by Keith Ansell Pearson - How to Read Nietzsche Ch.1
     A reaction: A striking contrast to Aristotle (Idea 549). Personally I think my philosophy begins with confusion. Not that I endorse a Wittgenteinian view, that we are just trying to cure ourselves of self-inflicted wounds. Life is very complex and we are bit simple.
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 / F. Referring in Logic / 2. Descriptions / c. Theory of definite descriptions
For Russell, expressions dependent on contingent circumstances must be eliminated [Kaplan]
     Full Idea: It is a tenet of Russell's theory that all expressions, and especially definite descriptions, whose denotation is dependent upon contingent circumstances must be eliminated.
     From: David Kaplan (How to Russell a Frege-Church [1975], II)
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)
10. Modality / E. Possible worlds / 3. Transworld Objects / d. Haecceitism
'Haecceitism' says that sameness or difference of individuals is independent of appearances [Kaplan]
     Full Idea: The doctrine that we can ask whether this is the same individual in another possible world, and that a common 'thisness' may underlie extreme dissimilarity, or distinct thisnesses may underlie great resemblance, I call 'Haecceitism'.
     From: David Kaplan (How to Russell a Frege-Church [1975], IV)
     A reaction: Penelope Mackie emphasises that this doctrine, that each thing is somehow individuated, is not the same as believing in actual haecceities, specific properties which achieve the individuating.
'Haecceitism' is common thisness under dissimilarity, or distinct thisnesses under resemblance [Kaplan]
     Full Idea: That a common 'thisness' may underlie extreme dissimilarity or distinct thisnesses may underlie great resemblance I call 'haecceitism'. (I prefer the pronunciation Hex'-ee-i-tis-m).
     From: David Kaplan (How to Russell a Frege-Church [1975], IV)
     A reaction: [odd pronunciation, if 'haec' is pronounced haeek] The view seems to be very unpopular (e.g. with Lewis, Bird and Mumford). But there is an intuitive sense of whether or not two things are identical when they seem dissimilar.
If quantification into modal contexts is legitimate, that seems to imply some form of haecceitism [Kaplan]
     Full Idea: If one regards the usual form of quantification into modal and other intensional contexts - modality de re - as legitimate (without special explanations), then one seems committed to some form of haecceitism.
     From: David Kaplan (How to Russell a Frege-Church [1975], IV)
     A reaction: That is, modal reference requires fixed identities, irrespective of possible changes in properties. Why could one not refer to objects just as bundles of properties, with some sort of rules about when it ceased to be that particular bundle (keep 60%?)?