Combining Texts

All the ideas for '67: Platonic Questions', 'works' and 'On Certainty'

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9 ideas

5. Theory of Logic / A. Overview of Logic / 2. History of Logic

11022

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

11065

The inferential role of a logical constant constitutes its meaning [Gentzen, by Hanna]

11023

The logical connectives are 'defined' by their introduction rules [Gentzen]

11213

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

10067

Gentzen proved the consistency of arithmetic from assumptions beyond arithmetic [Gentzen, by Musgrave]

13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / a. Foundationalism

3597	Foundations need not precede other beliefs [Wittgenstein]

13. Knowledge Criteria / D. Scepticism / 6. Scepticism Critique

3596	Total doubt can't even get started [Wittgenstein, by Williams,M]

15. Nature of Minds / A. Nature of Mind / 2. Psuche

5960	When the soul is intelligent and harmonious, it is part of god and derives from god [Plutarch]

19. Language / A. Nature of Meaning / 10. Denial of Meanings

4721	If you are not certain of any fact, you cannot be certain of the meaning of your words either [Wittgenstein]