Combining Texts

Ideas for 'On the Question of Absolute Undecidability', 'Analyzing Modality' and 'Mereology'

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3 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)
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
Maybe set theory need not be well-founded [Varzi]
     Full Idea: There are some proposals for non-well-founded set theory (tolerating cases of self-membership and membership circularities).
     From: Achille Varzi (Mereology [2003], 2.1)
     A reaction: [He cites Aczel 1988, and Barwise and Moss 1996]