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All the ideas for 'What is Logic?st1=Ian Hacking', 'Absolute Necessities' and 'What is Philosophy?'

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33 ideas

1. Philosophy / D. Nature of Philosophy / 1. Philosophy
Philosophy is in a perpetual state of digression [Deleuze/Guattari]
1. Philosophy / D. Nature of Philosophy / 3. Philosophy Defined
Philosophy is a concept-creating discipline [Deleuze/Guattari]
1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / a. Philosophy as worldly
Philosophy aims at what is interesting, remarkable or important - not at knowledge or truth [Deleuze/Guattari]
1. Philosophy / H. Continental Philosophy / 1. Continental Philosophy
The plague of philosophy is those who criticise without creating, and defend dead concepts [Deleuze/Guattari]
1. Philosophy / H. Continental Philosophy / 2. Phenomenology
Phenomenology needs art as logic needs science [Deleuze/Guattari]
2. Reason / C. Styles of Reason / 3. Eristic
'Eris' is the divinity of conflict, the opposite of Philia, the god of friendship [Deleuze/Guattari]
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
'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [Hacking]
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]
5. Theory of Logic / A. Overview of Logic / 3. Value of Logic
Logic has an infantile idea of philosophy [Deleuze/Guattari]
Logic hates philosophy, and wishes to supplant it [Deleuze/Guattari]
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]
10. Modality / A. Necessity / 2. Nature of Necessity
Absolute necessity might be achievable either logically or metaphysically [Hale]
10. Modality / A. Necessity / 3. Types of Necessity
Maybe not-p is logically possible, but p is metaphysically necessary, so the latter is not absolute [Hale]
A strong necessity entails a weaker one, but not conversely; possibilities go the other way [Hale]
'Relative' necessity is just a logical consequence of some statements ('strong' if they are all true) [Hale]
10. Modality / A. Necessity / 5. Metaphysical Necessity
Metaphysical necessity says there is no possibility of falsehood [Hale]
10. Modality / A. Necessity / 6. Logical Necessity
'Broadly' logical necessities are derived (in a structure) entirely from the concepts [Hale]
Logical necessities are true in virtue of the nature of all logical concepts [Hale]
10. Modality / C. Sources of Modality / 4. Necessity from Concepts
Conceptual necessities are made true by all concepts [Hale]
11. Knowledge Aims / B. Certain Knowledge / 4. The Cogito
We cannot judge the Cogito. Must we begin? Must we start from certainty? Can 'I' relate to thought? [Deleuze/Guattari]
14. Science / B. Scientific Theories / 4. Paradigm
Concepts are superior because they make us more aware, and change our thinking [Deleuze/Guattari]
15. Nature of Minds / A. Nature of Mind / 4. Other Minds / a. Other minds
Other people completely revise our perceptions, because they are possible worlds [Deleuze/Guattari]
18. Thought / C. Content / 6. Broad Content
Phenomenology says thought is part of the world [Deleuze/Guattari]
18. Thought / D. Concepts / 1. Concepts / a. Nature of concepts
The logical attitude tries to turn concepts into functions, when they are really forms or forces [Deleuze/Guattari]
28. God / C. Attitudes to God / 5. Atheism
Atheism is the philosopher's serenity, and philosophy's achievement [Deleuze/Guattari]