Combining Philosophers

All the ideas for Jonathan Barnes, Peter Koellner and James Baillie

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10 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 / D. Assumptions for Logic / 4. Identity in Logic
In logic identity involves reflexivity (x=x), symmetry (if x=y, then y=x) and transitivity (if x=y and y=z, then x=z) [Baillie]
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]
18. Thought / E. Abstraction / 8. Abstractionism Critique
Abstraction from an ambiguous concept like 'mole' will define them as the same [Barnes,J]
Abstraction cannot produce the concept of a 'game', as there is no one common feature [Barnes,J]
Defining concepts by abstractions will collect together far too many attributes from entities [Barnes,J]