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All the ideas for 'What is Logic?st1=Ian Hacking', 'Emotivism' and 'Maxims'

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25 ideas

1. Philosophy / A. Wisdom / 2. Wise People
To try to be wise all on one's own is folly [Rochefoucauld]
2. Reason / D. Definition / 3. Types of Definition
A decent modern definition should always imply a semantics [Hacking]
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 / 7. Second-Order Logic
Second-order completeness seems to need intensional entities and possible worlds [Hacking]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
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]
15. Nature of Minds / B. Features of Minds / 2. Unconscious Mind
La Rochefoucauld's idea of disguised self-love implies an unconscious mind [Rochefoucauld, by Sartre]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / h. Expressivism
Two people might agree in their emotional moral attitude while disagreeing in their judgement [Brink]
Emotivists find it hard to analyse assertions of moral principles, rather than actual judgements [Brink]
Emotivists claim to explain moral motivation by basing morality on non-cognitive attitudes [Brink]
Emotivists tend to favour a redundancy theory of truth, making moral judgement meaningless [Brink]
Emotivism implies relativism about moral meanings, but critics say disagreements are about moral reference [Brink]
How can emotivists explain someone who recognises morality but is indifferent to it? [Brink]
22. Metaethics / B. Value / 2. Values / g. Love
Judging by effects, love looks more like hatred than friendship [Rochefoucauld]
22. Metaethics / C. The Good / 1. Goodness / e. Good as knowledge
Supreme cleverness is knowledge of the real value of things [Rochefoucauld]
22. Metaethics / C. The Good / 2. Happiness / d. Routes to happiness
Realising our future misery is a kind of happiness [Rochefoucauld]
23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / c. Motivation for virtue
Virtue doesn't go far without the support of vanity [Rochefoucauld]
23. Ethics / C. Virtue Theory / 4. External Goods / d. Friendship
True friendship is even rarer than true love [Rochefoucauld]
23. Ethics / F. Existentialism / 4. Boredom
We are bored by people to whom we ourselves are boring [Rochefoucauld]