Combining Texts

All the ideas for 'Geometrical Method and Metaphysics', 'The Ultimate Constituents of Matter' and 'Higher-Order Logic'

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22 ideas

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]
4. Formal Logic / F. Set Theory ST / 8. Critique of Set Theory
Classes, grouped by a convenient property, are logical constructions [Russell]
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]
7. Existence / D. Theories of Reality / 4. Anti-realism
Visible things are physical and external, but only exist when viewed [Russell]
8. Modes of Existence / B. Properties / 11. Properties as Sets
Logicians use 'property' and 'set' interchangeably, with little hanging on it [Shapiro]
12. Knowledge Sources / B. Perception / 4. Sense Data / b. Nature of sense-data
If my body literally lost its mind, the object seen when I see a flash would still exist [Russell]
Sense-data are purely physical [Russell]
14. Science / D. Explanation / 2. Types of Explanation / g. Causal explanations
Minds are best explained by their ends, and bodies by efficient causes [Leibniz]
16. Persons / D. Continuity of the Self / 2. Mental Continuity / b. Self as mental continuity
A man is a succession of momentary men, bound by continuity and causation [Russell]
17. Mind and Body / E. Mind as Physical / 2. Reduction of Mind
We could probably, in principle, infer minds from brains, and brains from minds [Russell]
27. Natural Reality / B. Modern Physics / 4. Standard Model / a. Concept of matter
Matter is a logical construction [Russell]
Matter requires a division into time-corpuscles as well as space-corpuscles [Russell]
27. Natural Reality / C. Space / 2. Space
Six dimensions are needed for a particular, three within its own space, and three to locate that space [Russell]