Combining Texts

All the ideas for 'Abstract of 'The Fourfold Root'', 'Knowledge and the State of Nature' and 'What are Sets and What are they For?'

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17 ideas

2. Reason / B. Laws of Thought / 2. Sufficient Reason
'There is nothing without a reason why it should be rather than not be' (a generalisation of 'Why?') [Schopenhauer]
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 / C. Sources of Modality / 1. Sources of Necessity
All necessity arises from causation, which is conditioned; there is no absolute or unconditioned necessity [Schopenhauer]
11. Knowledge Aims / A. Knowledge / 2. Understanding
All understanding is an immediate apprehension of the causal relation [Schopenhauer]
11. Knowledge Aims / A. Knowledge / 3. Value of Knowledge
We have the concept of 'knowledge' as a label for good informants [Craig, by Fricker,M]
16. Persons / C. Self-Awareness / 2. Knowing the Self
What we know in ourselves is not a knower but a will [Schopenhauer]
16. Persons / D. Continuity of the Self / 3. Reference of 'I'
The knot of the world is the use of 'I' to refer to both willing and knowing [Schopenhauer]
27. Natural Reality / D. Time / 1. Nature of Time / b. Relative time
Time may be defined as the possibility of mutually exclusive conditions of the same thing [Schopenhauer]