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All the ideas for 'What is Logic?st1=Ian Hacking', 'Positivism and Realism' and 'The Sentiment of Rationality'

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30 ideas

1. Philosophy / A. Wisdom / 1. Nature of Wisdom
It is wisdom to believe what you desire, because belief is needed to achieve it [James]
1. Philosophy / D. Nature of Philosophy / 1. Philosophy
All good philosophers start from a dumb conviction about which truths can be revealed [James]
1. Philosophy / E. Nature of Metaphysics / 3. Metaphysical Systems
A complete system is just a classification of the whole world's ingredients [James]
1. Philosophy / E. Nature of Metaphysics / 7. Against Metaphysics
The empiricist says that metaphysics is meaningless, rather than false [Schlick]
2. Reason / A. Nature of Reason / 5. Objectivity
A single explanation must have a single point of view [James]
2. Reason / B. Laws of Thought / 6. Ockham's Razor
Our greatest pleasure is the economy of reducing chaotic facts to one single fact [James]
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 / 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]
7. Existence / E. Categories / 2. Categorisation
Classification can only ever be for a particular purpose [James]
14. Science / A. Basis of Science / 1. Observation
Scientific genius extracts more than other people from the same evidence [James]
14. Science / A. Basis of Science / 6. Falsification
Experimenters assume the theory is true, and stick to it as long as result don't disappoint [James]
14. Science / C. Induction / 3. Limits of Induction
We can't know if the laws of nature are stable, but we must postulate it or assume it [James]
14. Science / C. Induction / 6. Bayes's Theorem
Trying to assess probabilities by mere calculation is absurd and impossible [James]
14. Science / D. Explanation / 2. Types of Explanation / j. Explanations by reduction
We have a passion for knowing the parts of something, rather than the whole [James]
15. Nature of Minds / A. Nature of Mind / 1. Mind / b. Purpose of mind
The mind has evolved entirely for practical interests, seen in our reflex actions [James]
15. Nature of Minds / A. Nature of Mind / 7. Animal Minds
Dogs' curiosity only concerns what will happen next [James]
18. Thought / A. Modes of Thought / 5. Rationality / a. Rationality
How can the ground of rationality be itself rational? [James]
18. Thought / A. Modes of Thought / 5. Rationality / b. Human rationality
It seems that we feel rational when we detect no irrationality [James]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / d. Biological ethics
Evolution suggests prevailing or survival as a new criterion of right and wrong [James]
26. Natural Theory / C. Causation / 8. Particular Causation / d. Selecting the cause
Understanding by means of causes is useless if they are not reduced to a minimum number [James]
29. Religion / B. Monotheistic Religion / 4. Christianity / a. Christianity
Early Christianity says God recognises the neglected weak and tender impulses [James]