Combining Texts

All the ideas for '75: Is 'Live Unknown' a Wise Precept?', 'works' and 'Grundlagen (Foundations of Theory of Manifolds)'

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8 ideas

4. Formal Logic / F. Set Theory ST / 1. Set Theory
Cantor developed sets from a progression into infinity by addition, multiplication and exponentiation [Cantor, by Lavine]
5. Theory of Logic / A. Overview of Logic / 2. History of Logic
Gentzen introduced a natural deduction calculus (NK) in 1934 [Gentzen, by Read]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
The inferential role of a logical constant constitutes its meaning [Gentzen, by Hanna]
The logical connectives are 'defined' by their introduction rules [Gentzen]
Each logical symbol has an 'introduction' rule to define it, and hence an 'elimination' rule [Gentzen]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
Ordinals are generated by endless succession, followed by a limit ordinal [Cantor, by Lavine]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / g. Incompleteness of Arithmetic
Gentzen proved the consistency of arithmetic from assumptions beyond arithmetic [Gentzen, by Musgrave]
15. Nature of Minds / A. Nature of Mind / 2. Psuche
Some philosophers say the soul is light [Plutarch]