Combining Texts

All the ideas for 'Symbolic Reasoning', 'Isagoge ('Introduction')' and 'Explanation in Mathematics'

expand these ideas     |    start again     |     specify just one area for these texts

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3 ideas

4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set

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The null class is the class with all the non-existents as its members [MacColl, by Lackey]

8. Modes of Existence / D. Universals / 1. Universals

15034

Are genera and species real or conceptual? bodies or incorporeal? in sensibles or separate from them? [Porphyry]

9. Objects / D. Essence of Objects / 7. Essence and Necessity / b. Essence not necessities

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Essences are no use in mathematics, if all mathematical truths are necessary [Mancosu]