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All the ideas for 'fragments/reports', 'Truth and Truthmakers' and 'Introduction to the Philosophy of Mathematics'

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54 ideas

1. Philosophy / E. Nature of Metaphysics / 5. Metaphysics beyond Science
All metaphysical discussion should be guided by a quest for truthmakers [Armstrong]
3. Truth / B. Truthmakers / 4. Truthmaker Necessitarianism
Truth-making can't be entailment, because truthmakers are portions of reality [Armstrong]
Armstrong says truthmakers necessitate their truth, where 'necessitate' is a primitive relation [Armstrong, by MacBride]
3. Truth / B. Truthmakers / 6. Making Negative Truths
Negative truths have as truthmakers all states of affairs relevant to the truth [Armstrong]
The nature of arctic animals is truthmaker for the absence of penguins there [Armstrong]
3. Truth / B. Truthmakers / 7. Making Modal Truths
One truthmaker will do for a contingent truth and for its contradictory [Armstrong]
In mathematics, truthmakers are possible instantiations of structures [Armstrong]
The truthmakers for possible unicorns are the elements in their combination [Armstrong]
What is the truthmaker for 'it is possible that there could have been nothing'? [Armstrong]
3. Truth / B. Truthmakers / 8. Making General Truths
Necessitating general truthmakers must also specify their limits [Armstrong]
4. Formal Logic / E. Nonclassical Logics / 2. Intuitionist Logic
Showing a disproof is impossible is not a proof, so don't eliminate double negation [Colyvan]
Rejecting double negation elimination undermines reductio proofs [Colyvan]
4. Formal Logic / F. Set Theory ST / 1. Set Theory
The set theory brackets { } assert that the member is a unit [Armstrong]
4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set
For 'there is a class with no members' we don't need the null set as truthmaker [Armstrong]
5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
Excluded middle says P or not-P; bivalence says P is either true or false [Colyvan]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
Löwenheim proved his result for a first-order sentence, and Skolem generalised it [Colyvan]
5. Theory of Logic / K. Features of Logics / 1. Axiomatisation
Axioms are 'categorical' if all of their models are isomorphic [Colyvan]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
Ordinal numbers represent order relations [Colyvan]
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / a. Units
Classes have cardinalities, so their members must all be treated as units [Armstrong]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / a. The Infinite
Intuitionists only accept a few safe infinities [Colyvan]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / j. Infinite divisibility
Infinitesimals were sometimes zero, and sometimes close to zero [Colyvan]
6. Mathematics / B. Foundations for Mathematics / 1. Foundations for Mathematics
Reducing real numbers to rationals suggested arithmetic as the foundation of maths [Colyvan]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / f. Mathematical induction
Transfinite induction moves from all cases, up to the limit ordinal [Colyvan]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
Most mathematical proofs are using set theory, but without saying so [Colyvan]
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / a. Structuralism
Structuralism say only 'up to isomorphism' matters because that is all there is to it [Colyvan]
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / e. Structuralism critique
If 'in re' structures relies on the world, does the world contain rich enough structures? [Colyvan]
7. Existence / C. Structure of Existence / 6. Fundamentals / d. Logical atoms
Logical atomism builds on the simple properties, but are they the only possible properties? [Armstrong]
7. Existence / D. Theories of Reality / 5. Naturalism
'Naturalism' says only the world of space-time exists [Armstrong]
7. Existence / D. Theories of Reality / 9. States of Affairs
Truthmaking needs states of affairs, to unite particulars with tropes or universals. [Armstrong]
8. Modes of Existence / B. Properties / 2. Need for Properties
We need properties, as minimal truthmakers for the truths about objects [Armstrong]
8. Modes of Existence / B. Properties / 3. Types of Properties
The determinates of a determinable must be incompatible with each other [Armstrong]
Length is a 'determinable' property, and one mile is one its 'determinates' [Armstrong]
8. Modes of Existence / B. Properties / 13. Tropes / a. Nature of tropes
If tropes are non-transferable, then they necessarily belong to their particular substance [Armstrong]
8. Modes of Existence / C. Powers and Dispositions / 5. Powers and Properties
Properties are not powers - they just have powers [Armstrong]
8. Modes of Existence / C. Powers and Dispositions / 7. Against Powers
Powers must result in some non-powers, or there would only be potential without result [Armstrong]
How does the power of gravity know the distance it acts over? [Armstrong]
8. Modes of Existence / E. Nominalism / 5. Class Nominalism
The class of similar things is much too big a truthmaker for the feature of a particular [Armstrong]
9. Objects / F. Identity among Objects / 1. Concept of Identity
When entities contain entities, or overlap with them, there is 'partial' identity [Armstrong]
10. Modality / E. Possible worlds / 1. Possible Worlds / e. Against possible worlds
Possible worlds don't fix necessities; intrinsic necessities imply the extension in worlds [Armstrong]
14. Science / C. Induction / 6. Bayes's Theorem
Probability supports Bayesianism better as degrees of belief than as ratios of frequencies [Colyvan]
14. Science / D. Explanation / 2. Types of Explanation / e. Lawlike explanations
Mathematics can reveal structural similarities in diverse systems [Colyvan]
14. Science / D. Explanation / 2. Types of Explanation / f. Necessity in explanations
Mathematics can show why some surprising events have to occur [Colyvan]
14. Science / D. Explanation / 2. Types of Explanation / m. Explanation by proof
Proof by cases (by 'exhaustion') is said to be unexplanatory [Colyvan]
Reductio proofs do not seem to be very explanatory [Colyvan]
If inductive proofs hold because of the structure of natural numbers, they may explain theorems [Colyvan]
Can a proof that no one understands (of the four-colour theorem) really be a proof? [Colyvan]
15. Nature of Minds / C. Capacities of Minds / 5. Generalisation by mind
Mathematical generalisation is by extending a system, or by abstracting away from it [Colyvan]
General truths are a type of negative truth, saying there are no more ravens than black ones [Armstrong]
19. Language / D. Propositions / 2. Abstract Propositions / a. Propositions as sense
For all being, there is a potential proposition which expresses its existence and nature [Armstrong]
A realm of abstract propositions is causally inert, so has no explanatory value [Armstrong]
26. Natural Theory / A. Speculations on Nature / 5. Infinite in Nature
Archelaus was the first person to say that the universe is boundless [Archelaus, by Diog. Laertius]
26. Natural Theory / C. Causation / 4. Naturalised causation
Negative causations supervene on positive causations plus their laws? [Armstrong]
27. Natural Reality / D. Time / 3. Parts of Time / e. Present moment
The pure present moment is too brief to be experienced [Armstrong]
27. Natural Reality / G. Biology / 3. Evolution
Archelaus said life began in a primeval slime [Archelaus, by Schofield]