Combining Texts

All the ideas for 'fragments/reports', 'The Essence of Reference' and 'What are Sets and What are they For?'

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18 ideas

4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set
14240 The empty set is something, not nothing! [Oliver/Smiley]
14239 The empty set is usually derived from Separation, but it also seems to need Infinity [Oliver/Smiley]
14241 We don't need the empty set to express non-existence, as there are other ways to do that [Oliver/Smiley]
14242 Maybe we can treat the empty set symbol as just meaning an empty term [Oliver/Smiley]
4. Formal Logic / F. Set Theory ST / 3. Types of Set / c. Unit (Singleton) Sets
14243 The unit set may be needed to express intersections that leave a single member [Oliver/Smiley]
5. Theory of Logic / F. Referring in Logic / 1. Naming / e. Empty names
10429 It is best to say that a name designates iff there is something for it to designate [Sainsbury]
5. Theory of Logic / F. Referring in Logic / 2. Descriptions / b. Definite descriptions
10425 Definite descriptions may not be referring expressions, since they can fail to refer [Sainsbury]
10438 Definite descriptions are usually rigid in subject, but not in predicate, position [Sainsbury]
5. Theory of Logic / G. Quantification / 6. Plural Quantification
14234 If you only refer to objects one at a time, you need sets in order to refer to a plurality [Oliver/Smiley]
14237 We can use plural language to refer to the set theory domain, to avoid calling it a 'set' [Oliver/Smiley]
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
14245 Logical truths are true no matter what exists - but predicate calculus insists that something exists [Oliver/Smiley]
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / g. Applying mathematics
14246 If mathematics purely concerned mathematical objects, there would be no applied mathematics [Oliver/Smiley]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
14247 Sets might either represent the numbers, or be the numbers, or replace the numbers [Oliver/Smiley]
9. Objects / E. Objects over Time / 8. Continuity of Rivers
579 Cratylus said you couldn't even step into the same river once [Cratylus, by Aristotle]
13. Knowledge Criteria / D. Scepticism / 1. Scepticism
578 Cratylus decided speech was hopeless, and his only expression was the movement of a finger [Cratylus, by Aristotle]
19. Language / B. Reference / 3. Direct Reference / b. Causal reference
10432 A new usage of a name could arise from a mistaken baptism of nothing [Sainsbury]
19. Language / B. Reference / 5. Speaker's Reference
10434 Even a quantifier like 'someone' can be used referentially [Sainsbury]
26. Natural Theory / A. Speculations on Nature / 3. Natural Function
10431 Things are thought to have a function, even when they can't perform them [Sainsbury]