Combining Texts

All the ideas for 'Counterfactuals', 'Sententia on 'Posterior Analytics'' and 'What are Sets and What are they For?'

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14 ideas

4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set
The empty set is usually derived from Separation, but it also seems to need Infinity [Oliver/Smiley]
The empty set is something, not nothing! [Oliver/Smiley]
We don't need the empty set to express non-existence, as there are other ways to do that [Oliver/Smiley]
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
The unit set may be needed to express intersections that leave a single member [Oliver/Smiley]
5. Theory of Logic / G. Quantification / 6. Plural Quantification
If you only refer to objects one at a time, you need sets in order to refer to a plurality [Oliver/Smiley]
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
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
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
Sets might either represent the numbers, or be the numbers, or replace the numbers [Oliver/Smiley]
10. Modality / B. Possibility / 8. Conditionals / c. Truth-function conditionals
Lewis says indicative conditionals are truth-functional [Lewis, by Jackson]
10. Modality / B. Possibility / 9. Counterfactuals
In good counterfactuals the consequent holds in world like ours except that the antecedent is true [Lewis, by Horwich]
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / a. Coherence as justification
The fullest knowledge places a conclusion within an accurate theory [Aquinas, by Kretzmann/Stump]
26. Natural Theory / D. Laws of Nature / 4. Regularities / b. Best system theory
A law of nature is a general axiom of the deductive system that is best for simplicity and strength [Lewis]