Combining Texts

All the ideas for 'Good and Evil', 'Higher-Order Logic' and 'Causation and Laws of Nature'

expand these ideas     |    start again     |     specify just one area for these texts


21 ideas

1. Philosophy / F. Analytic Philosophy / 3. Analysis of Preconditions
Analysis aims at secure necessary and sufficient conditions [Schaffer,J]
2. Reason / F. Fallacies / 1. Fallacy
'Reification' occurs if we mistake a concept for a thing [Schaffer,J]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / d. System T
T adds □p→p for reflexivity, and is ideal for modeling lawhood [Schaffer,J]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX
The axiom of choice is controversial, but it could be replaced [Shapiro]
5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
First-order logic is Complete, and Compact, with the Löwenheim-Skolem Theorems [Shapiro]
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
Some say that second-order logic is mathematics, not logic [Shapiro]
If the aim of logic is to codify inferences, second-order logic is useless [Shapiro]
5. Theory of Logic / B. Logical Consequence / 1. Logical Consequence
Logical consequence can be defined in terms of the logical terminology [Shapiro]
5. Theory of Logic / G. Quantification / 5. Second-Order Quantification
Second-order variables also range over properties, sets, relations or functions [Shapiro]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
Up Löwenheim-Skolem: if natural numbers satisfy wffs, then an infinite domain satisfies them [Shapiro]
The Löwenheim-Skolem Theorems fail for second-order languages with standard semantics [Shapiro]
The Löwenheim-Skolem theorem seems to be a defect of first-order logic [Shapiro]
Downward Löwenheim-Skolem: if there's an infinite model, there is a countable model [Shapiro]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / e. Peano arithmetic 2nd-order
Second-order logic has the expressive power for mathematics, but an unworkable model theory [Shapiro]
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / b. Indispensability of mathematics
If a notion is ontologically basic, it should be needed in our best attempt at science [Schaffer,J]
7. Existence / C. Structure of Existence / 2. Reduction
Three types of reduction: Theoretical (of terms), Definitional (of concepts), Ontological (of reality) [Schaffer,J]
8. Modes of Existence / B. Properties / 11. Properties as Sets
Logicians use 'property' and 'set' interchangeably, with little hanging on it [Shapiro]
8. Modes of Existence / B. Properties / 13. Tropes / a. Nature of tropes
Tropes are the same as events [Schaffer,J]
9. Objects / A. Existence of Objects / 5. Individuation / a. Individuation
Individuation aims to count entities, by saying when there is one [Schaffer,J]
10. Modality / D. Knowledge of Modality / 4. Conceivable as Possible / a. Conceivable as possible
Only ideal conceivability could indicate what is possible [Schaffer,J]
22. Metaethics / C. The Good / 1. Goodness / a. Form of the Good
'Good' is an attributive adjective like 'large', not predicative like 'red' [Geach, by Foot]