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Ideas for 'Frege's Theory of Numbers', 'The Metaphysics of Scientific Realism' and 'works'

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3 ideas

6. Mathematics / B. Foundations for Mathematics / 1. Foundations for Mathematics
Mathematics is the formal study of the categorical dimensions of things [Ellis]
     Full Idea: I wish to explore the idea that mathematics is the formal study of the categorical dimensions of things.
     From: Brian Ellis (The Metaphysics of Scientific Realism [2009], 6)
     A reaction: Categorical dimensions are spatiotemporal relations and other non-causal properties. Ellis defends categorical properties as an aspect of science. The obvious connection seems to be with structuralism in mathematics. Shapiro is sympathetic.
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / g. Incompleteness of Arithmetic
Gödel eventually hoped for a generalised completeness theorem leaving nothing undecidable [Gödel, by Koellner]
     Full Idea: Eventually Gödel ...expressed the hope that there might be a generalised completeness theorem according to which there are no absolutely undecidable sentences.
     From: report of Kurt Gödel (works [1930]) by Peter Koellner - On the Question of Absolute Undecidability Intro
     A reaction: This comes as a bit of a shock to those who associate him with the inherent undecidability of reality.
The real reason for Incompleteness in arithmetic is inability to define truth in a language [Gödel]
     Full Idea: The concept of truth of sentences in a language cannot be defined in the language. This is the true reason for the existence of undecidable propositions in the formal systems containing arithmetic.
     From: Kurt Gödel (works [1930]), quoted by Peter Smith - Intro to Gödel's Theorems 21.6
     A reaction: [from a letter by Gödel] So they key to Incompleteness is Tarski's observations about truth. Highly significant, as I take it.