Combining Texts

All the ideas for 'fragments/reports', 'The Nature of Existence vol.2' and 'Elements of Set Theory'

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19 ideas

1. Philosophy / D. Nature of Philosophy / 3. Philosophy Defined
Even pointing a finger should only be done for a reason [Epictetus]
4. Formal Logic / F. Set Theory ST / 2. Mechanics of Set Theory / b. Terminology of ST
∈ says the whole set is in the other; ⊆ says the members of the subset are in the other [Enderton]
The 'ordered pair' <x,y> is defined to be {{x}, {x,y}} [Enderton]
A 'linear or total ordering' must be transitive and satisfy trichotomy [Enderton]
4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set
Note that {Φ} =/= Φ, because Φ ∈ {Φ} but Φ ∉ Φ [Enderton]
The empty set may look pointless, but many sets can be constructed from it [Enderton]
4. Formal Logic / F. Set Theory ST / 3. Types of Set / c. Unit (Singleton) Sets
The singleton is defined using the pairing axiom (as {x,x}) [Enderton]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / h. Axiom of Replacement VII
Fraenkel added Replacement, to give a theory of ordinal numbers [Enderton]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX
We can only define functions if Choice tells us which items are involved [Enderton]
7. Existence / B. Change in Existence / 1. Nature of Change
How could change consist of a conjunction of changeless facts? [McTaggart, by Le Poidevin]
Change is not just having two different qualities at different points in some series [McTaggart]
27. Natural Reality / D. Time / 1. Nature of Time / b. Relative time
For McTaggart time is seen either as fixed, or as relative to events [McTaggart, by Ayer]
27. Natural Reality / D. Time / 1. Nature of Time / i. Denying time
A-series time positions are contradictory, and yet all events occupy all of them! [McTaggart, by Le Poidevin]
Time involves change, only the A-series explains change, but it involves contradictions, so time is unreal [McTaggart, by Lowe]
27. Natural Reality / D. Time / 2. Passage of Time / a. Experience of time
There could be no time if nothing changed [McTaggart]
27. Natural Reality / D. Time / 2. Passage of Time / d. Time series
The B-series can be inferred from the A-series, but not the other way round [McTaggart, by Le Poidevin]
A-series uses past, present and future; B-series uses 'before' and 'after' [McTaggart, by Girle]
A-series expressions place things in time, and their truth varies; B-series is relative, and always true [McTaggart, by Lowe]
The B-series must depend on the A-series, because change must be explained [McTaggart, by Le Poidevin]