Combining Philosophers

All the ideas for Hermarchus, John L. Pollock and Gerhard Gentzen

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19 ideas

3. Truth / A. Truth Problems / 1. Truth
Rules of reasoning precede the concept of truth, and they are what characterize it [Pollock]
3. Truth / H. Deflationary Truth / 2. Deflationary Truth
We need the concept of truth for defeasible reasoning [Pollock]
5. Theory of Logic / A. Overview of Logic / 2. History of Logic
Gentzen introduced a natural deduction calculus (NK) in 1934 [Gentzen, by Read]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
The inferential role of a logical constant constitutes its meaning [Gentzen, by Hanna]
The logical connectives are 'defined' by their introduction rules [Gentzen]
Each logical symbol has an 'introduction' rule to define it, and hence an 'elimination' rule [Gentzen]
5. Theory of Logic / H. Proof Systems / 4. Natural Deduction
Natural deduction shows the heart of reasoning (and sequent calculus is just a tool) [Gentzen, by Hacking]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / g. Incompleteness of Arithmetic
Gentzen proved the consistency of arithmetic from assumptions beyond arithmetic [Gentzen, by Musgrave]
10. Modality / A. Necessity / 2. Nature of Necessity
Statements about necessities need not be necessarily true [Pollock]
11. Knowledge Aims / A. Knowledge / 4. Belief / f. Animal beliefs
Defeasible reasoning requires us to be able to think about our thoughts [Pollock]
13. Knowledge Criteria / A. Justification Problems / 1. Justification / b. Need for justification
What we want to know is - when is it all right to believe something? [Pollock]
13. Knowledge Criteria / A. Justification Problems / 2. Justification Challenges / c. Knowledge closure
Logical entailments are not always reasons for beliefs, because they may be irrelevant [Pollock]
13. Knowledge Criteria / A. Justification Problems / 3. Internal or External / a. Pro-internalism
Epistemic norms are internalised procedural rules for reasoning [Pollock]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / c. Empirical foundations
Reasons are always for beliefs, but a perceptual state is a reason without itself being a belief [Pollock]
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / c. Coherentism critique
If we have to appeal explicitly to epistemic norms, that will produce an infinite regress [Pollock]
13. Knowledge Criteria / C. External Justification / 1. External Justification
Norm Externalism says norms must be internal, but their selection is partly external [Pollock]
Externalists tend to take a third-person point of view of epistemology [Pollock]
13. Knowledge Criteria / C. External Justification / 10. Anti External Justification
Belief externalism is false, because external considerations cannot be internalized for actual use [Pollock]
25. Social Practice / F. Life Issues / 6. Animal Rights
Animals are dangerous and nourishing, and can't form contracts of justice [Hermarchus, by Sedley]