Combining Texts

All the ideas for 'fragments/reports', 'Commentary on Sentences' and 'works'

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10 ideas

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 / 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]
7. Existence / A. Nature of Existence / 3. Being / d. Non-being
Not-Being obviously doesn't exist, and the five modes of Being are all impossible [Gorgias, by Diog. Laertius]
8. Modes of Existence / B. Properties / 8. Properties as Modes
Accidents always remain suited to a subject [Bonaventura]
9. Objects / E. Objects over Time / 6. Successive Things
Successive things reduce to permanent things [Bonaventura]
19. Language / F. Communication / 1. Rhetoric
Gorgias says rhetoric is the best of arts, because it enslaves without using force [Gorgias, by Plato]
Destroy seriousness with laughter, and laughter with seriousness [Gorgias]