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All the ideas for 'What is Logic?st1=Ian Hacking', 'Thinking About Mathematics' and 'Relativism'

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50 ideas

1. Philosophy / C. History of Philosophy / 5. Modern Philosophy / d. Contemporary philosophy
There has been a distinct 'Social Turn' in recent philosophy, like the earlier 'Linguistic Turn' [O'Grady]
2. Reason / A. Nature of Reason / 4. Aims of Reason
Good reasoning will avoid contradiction, enhance coherence, not ignore evidence, and maximise evidence [O'Grady]
2. Reason / D. Definition / 3. Types of Definition
A decent modern definition should always imply a semantics [Hacking]
2. Reason / E. Argument / 7. Thought Experiments
Just as maps must simplify their subject matter, so thought has to be reductionist about reality [O'Grady]
3. Truth / A. Truth Problems / 1. Truth
To say a relative truth is inexpressible in other frameworks is 'weak', while saying it is false is 'strong' [O'Grady]
The epistemic theory of truth presents it as 'that which is licensed by our best theory of reality' [O'Grady]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / d. Basic theorems of PL
Gentzen's Cut Rule (or transitivity of deduction) is 'If A |- B and B |- C, then A |- C' [Hacking]
Only Cut reduces complexity, so logic is constructive without it, and it can be dispensed with [Hacking]
'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [Hacking]
5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
The various logics are abstractions made from terms like 'if...then' in English [Hacking]
5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
First-order logic is the strongest complete compact theory with Löwenheim-Skolem [Hacking]
A limitation of first-order logic is that it cannot handle branching quantifiers [Hacking]
5. Theory of Logic / A. Overview of Logic / 6. Classical Logic
Logical relativism appears if we allow more than one legitimate logical system [O'Grady]
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
Second-order completeness seems to need intensional entities and possible worlds [Hacking]
5. Theory of Logic / D. Assumptions for Logic / 1. Bivalence
A third value for truth might be "indeterminate", or a point on a scale between 'true' and 'false' [O'Grady]
5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
Intuitionists deny excluded middle, because it is committed to transcendent truth or objects [Shapiro]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
Wittgenstein reduced Russell's five primitive logical symbols to a mere one [O'Grady]
With a pure notion of truth and consequence, the meanings of connectives are fixed syntactically [Hacking]
5. Theory of Logic / E. Structures of Logic / 4. Variables in Logic
Perhaps variables could be dispensed with, by arrows joining places in the scope of quantifiers [Hacking]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / b. Types of number
The number 3 is presumably identical as a natural, an integer, a rational, a real, and complex [Shapiro]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / h. Reals from Cauchy
Cauchy gave a formal definition of a converging sequence. [Shapiro]
6. Mathematics / B. Foundations for Mathematics / 1. Foundations for Mathematics
Categories are the best foundation for mathematics [Shapiro]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / f. Zermelo numbers
Two definitions of 3 in terms of sets disagree over whether 1 is a member of 3 [Shapiro]
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / a. Structuralism
Numbers do not exist independently; the essence of a number is its relations to other numbers [Shapiro]
A 'system' is related objects; a 'pattern' or 'structure' abstracts the pure relations from them [Shapiro]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / d. Logicism critique
Logicism seems to be a non-starter if (as is widely held) logic has no ontology of its own [Shapiro]
6. Mathematics / C. Sources of Mathematics / 7. Formalism
Term Formalism says mathematics is just about symbols - but real numbers have no names [Shapiro]
Game Formalism is just a matter of rules, like chess - but then why is it useful in science? [Shapiro]
Deductivism says mathematics is logical consequences of uninterpreted axioms [Shapiro]
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / b. Intuitionism
Critics resent the way intuitionism cripples mathematics, but it allows new important distinctions [Shapiro]
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / c. Conceptualism
Conceptualist are just realists or idealist or nominalists, depending on their view of concepts [Shapiro]
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / d. Predicativism
'Impredicative' definitions refer to the thing being described [Shapiro]
7. Existence / D. Theories of Reality / 4. Anti-realism
Anti-realists say our theories (such as wave-particle duality) give reality incompatible properties [O'Grady]
7. Existence / D. Theories of Reality / 8. Facts / a. Facts
What counts as a fact partly depends on the availability of human concepts to describe them [O'Grady]
9. Objects / A. Existence of Objects / 5. Individuation / a. Individuation
We may say that objects have intrinsic identity conditions, but still allow multiple accounts of them [O'Grady]
10. Modality / D. Knowledge of Modality / 1. A Priori Necessary
Maybe developments in logic and geometry have shown that the a priori may be relative [O'Grady]
12. Knowledge Sources / B. Perception / 4. Sense Data / d. Sense-data problems
Sense-data are only safe from scepticism if they are primitive and unconceptualised [O'Grady]
12. Knowledge Sources / C. Rationalism / 1. Rationalism
Rationalism tries to apply mathematical methodology to all of knowledge [Shapiro]
13. Knowledge Criteria / A. Justification Problems / 1. Justification / a. Justification issues
Modern epistemology centres on debates about foundations, and about external justification [O'Grady]
13. Knowledge Criteria / A. Justification Problems / 3. Internal or External / a. Pro-internalism
Internalists say the reasons for belief must be available to the subject, and externalists deny this [O'Grady]
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / a. Coherence as justification
Coherence involves support from explanation and evidence, and also probability and confirmation [O'Grady]
13. Knowledge Criteria / E. Relativism / 1. Relativism
Ontological relativists are anti-realists, who deny that our theories carve nature at the joints [O'Grady]
13. Knowledge Criteria / E. Relativism / 2. Knowledge as Convention
Contextualism says that knowledge is relative to its context; 'empty' depends on your interests [O'Grady]
14. Science / B. Scientific Theories / 5. Commensurability
One may understand a realm of ideas, but be unable to judge their rationality or truth [O'Grady]
19. Language / A. Nature of Meaning / 5. Meaning as Verification
Verificationism was attacked by the deniers of the analytic-synthetic distinction, needed for 'facts' [O'Grady]
19. Language / E. Analyticity / 3. Analytic and Synthetic
If we abandon the analytic-synthetic distinction, scepticism about meaning may be inevitable [O'Grady]
19. Language / F. Communication / 6. Interpreting Language / a. Translation
Early Quine says all beliefs could be otherwise, but later he said we would assume mistranslation [O'Grady]
19. Language / F. Communication / 6. Interpreting Language / c. Principle of charity
Cryptographers can recognise that something is a language, without translating it [O'Grady]
29. Religion / D. Religious Issues / 1. Religious Commitment / e. Fideism
The chief problem for fideists is other fideists who hold contrary ideas [O'Grady]