Combining Texts

All the ideas for 'Higher-Order Logic', 'How to Make our Ideas Clear' and 'No Understanding without Explanation'

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19 ideas

3. Truth / E. Pragmatic Truth / 1. Pragmatic Truth
7661 Truth is the opinion fated to be ultimately agreed by all investigators [Peirce]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX
10301 The axiom of choice is controversial, but it could be replaced [Shapiro]
5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
10588 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
10298 Some say that second-order logic is mathematics, not logic [Shapiro]
10299 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
10300 Logical consequence can be defined in terms of the logical terminology [Shapiro]
5. Theory of Logic / G. Quantification / 5. Second-Order Quantification
10290 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
10590 Up Löwenheim-Skolem: if natural numbers satisfy wffs, then an infinite domain satisfies them [Shapiro]
10296 The Löwenheim-Skolem Theorems fail for second-order languages with standard semantics [Shapiro]
10297 The Löwenheim-Skolem theorem seems to be a defect of first-order logic [Shapiro]
10292 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
10294 Second-order logic has the expressive power for mathematics, but an unworkable model theory [Shapiro]
8. Modes of Existence / B. Properties / 11. Properties as Sets
10591 Logicians use 'property' and 'set' interchangeably, with little hanging on it [Shapiro]
11. Knowledge Aims / A. Knowledge / 2. Understanding
19089 Our whole conception of an object is its possible practical consequences [Peirce]
14365 Scientific understanding is always the grasping of a correct explanation [Strevens]
14368 We may 'understand that' the cat is on the mat, but not at all 'understand why' it is there [Strevens]
14369 Understanding is a precondition, comes in degrees, is active, and holistic - unlike explanation [Strevens]
11. Knowledge Aims / A. Knowledge / 4. Belief / b. Elements of beliefs
7660 We are aware of beliefs, they appease our doubts, and they are rules of action, or habits [Peirce]
19. Language / A. Nature of Meaning / 5. Meaning as Verification
14906 Non-positivist verificationism says only take a hypothesis seriously if it is scientifically based and testable [Ladyman/Ross on Peirce]