Combining Texts

All the ideas for 'Classical Cosmology (frags)', 'Introduction to the Theory of Logic' and 'Causation'

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34 ideas

4. Formal Logic / F. Set Theory ST / 1. Set Theory
Sets can be defined by 'enumeration', or by 'abstraction' (based on a property) [Zalabardo]
4. Formal Logic / F. Set Theory ST / 2. Mechanics of Set Theory / b. Terminology of ST
The 'Cartesian Product' of two sets relates them by pairing every element with every element [Zalabardo]
A 'partial ordering' is reflexive, antisymmetric and transitive [Zalabardo]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
Determinacy: an object is either in a set, or it isn't [Zalabardo]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / l. Axiom of Specification
Specification: Determinate totals of objects always make a set [Zalabardo]
5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
A first-order 'sentence' is a formula with no free variables [Zalabardo]
5. Theory of Logic / B. Logical Consequence / 4. Semantic Consequence |=
Γ |= φ for sentences if φ is true when all of Γ is true [Zalabardo]
Γ |= φ if φ is true when all of Γ is true, for all structures and interpretations [Zalabardo]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / b. Basic connectives
Propositional logic just needs ¬, and one of ∧, ∨ and → [Zalabardo]
5. Theory of Logic / I. Semantics of Logic / 1. Semantics of Logic
The semantics shows how truth values depend on instantiations of properties and relations [Zalabardo]
We can do semantics by looking at given propositions, or by building new ones [Zalabardo]
5. Theory of Logic / I. Semantics of Logic / 2. Formal Truth
We make a truth assignment to T and F, which may be true and false, but merely differ from one another [Zalabardo]
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
'Logically true' (|= φ) is true for every truth-assignment [Zalabardo]
Logically true sentences are true in all structures [Zalabardo]
5. Theory of Logic / I. Semantics of Logic / 4. Satisfaction
A sentence-set is 'satisfiable' if at least one truth-assignment makes them all true [Zalabardo]
Some formulas are 'satisfiable' if there is a structure and interpretation that makes them true [Zalabardo]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
A structure models a sentence if it is true in the model, and a set of sentences if they are all true in the model [Zalabardo]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / f. Mathematical induction
If a set is defined by induction, then proof by induction can be applied to it [Zalabardo]
8. Modes of Existence / C. Powers and Dispositions / 2. Powers as Basic
If dispositions are more fundamental than causes, then they won't conceptually reduce to them [Bird on Lewis]
10. Modality / B. Possibility / 9. Counterfactuals
For true counterfactuals, both antecedent and consequent true is closest to actuality [Lewis]
16. Persons / F. Free Will / 6. Determinism / a. Determinism
Determinism says there can't be two identical worlds up to a time, with identical laws, which then differ [Lewis]
19. Language / D. Propositions / 2. Abstract Propositions / b. Propositions as possible worlds
A proposition is a set of possible worlds where it is true [Lewis]
26. Natural Theory / C. Causation / 5. Direction of causation
A theory of causation should explain why cause precedes effect, not take it for granted [Lewis, by Field,H]
I reject making the direction of causation axiomatic, since that takes too much for granted [Lewis]
26. Natural Theory / C. Causation / 8. Particular Causation / d. Selecting the cause
It is just individious discrimination to pick out one cause and label it as 'the' cause [Lewis]
The modern regularity view says a cause is a member of a minimal set of sufficient conditions [Lewis]
26. Natural Theory / C. Causation / 9. General Causation / a. Constant conjunction
Regularity analyses could make c an effect of e, or an epiphenomenon, or inefficacious, or pre-empted [Lewis]
26. Natural Theory / C. Causation / 9. General Causation / c. Counterfactual causation
The counterfactual view says causes are necessary (rather than sufficient) for their effects [Lewis, by Bird]
Lewis has basic causation, counterfactuals, and a general ancestral (thus handling pre-emption) [Lewis, by Bird]
Counterfactual causation implies all laws are causal, which they aren't [Tooley on Lewis]
My counterfactual analysis applies to particular cases, not generalisations [Lewis]
One event causes another iff there is a causal chain from first to second [Lewis]
26. Natural Theory / D. Laws of Nature / 9. Counterfactual Claims
Lewis's account of counterfactuals is fine if we know what a law of nature is, but it won't explain the latter [Cohen,LJ on Lewis]
27. Natural Reality / E. Cosmology / 1. Cosmology
Is the cosmos open or closed, mechanical or teleological, alive or inanimate, and created or eternal? [Robinson,TM, by PG]