Combining Texts

All the ideas for 'fragments/reports', 'Notes on Logic' and 'Investigations into Logical Deduction'

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4 ideas

5. Theory of Logic / H. Proof Systems / 4. Natural Deduction

13832

Natural deduction shows the heart of reasoning (and sequent calculus is just a tool) [Gentzen, by Hacking]

7. Existence / D. Theories of Reality / 8. Facts / d. Negative facts

22312

Facts can be both positive and negative [Wittgenstein, by Potter]

26. Natural Theory / A. Speculations on Nature / 5. Infinite in Nature

1748	Archelaus was the first person to say that the universe is boundless [Archelaus, by Diog. Laertius]

27. Natural Reality / G. Biology / 3. Evolution

5989	Archelaus said life began in a primeval slime [Archelaus, by Schofield]