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All the ideas for 'What is Logic?st1=Ian Hacking', 'works' and 'Phaedo'

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33 ideas

1. Philosophy / A. Wisdom / 1. Nature of Wisdom
Wisdom makes virtue and true goodness possible [Plato]
1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / b. Philosophy as transcendent
Philosophy is a purification of the soul ready for the afterlife [Plato]
2. Reason / A. Nature of Reason / 3. Pure Reason
In investigation the body leads us astray, but the soul gets a clear view of the facts [Plato]
2. Reason / A. Nature of Reason / 7. Status of Reason
The greatest misfortune for a person is to develop a dislike for argument [Plato]
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]
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / f. Arithmetic
If you add one to one, which one becomes two, or do they both become two? [Plato]
8. Modes of Existence / A. Relations / 2. Internal Relations
If Simmias is taller than Socrates, that isn't a feature that is just in Simmias [Plato]
8. Modes of Existence / D. Universals / 6. Platonic Forms / a. Platonic Forms
We must have a prior knowledge of equality, if we see 'equal' things and realise they fall short of it [Plato]
8. Modes of Existence / D. Universals / 6. Platonic Forms / b. Partaking
There is only one source for all beauty [Plato]
Other things are named after the Forms because they participate in them [Plato]
9. Objects / E. Objects over Time / 9. Ship of Theseus
The ship which Theseus took to Crete is now sent to Delos crowned with flowers [Plato]
12. Knowledge Sources / A. A Priori Knowledge / 3. Innate Knowledge / b. Recollection doctrine
People are obviously recollecting when they react to a geometrical diagram [Plato]
If we feel the inadequacy of a resemblance, we must recollect the original [Plato]
12. Knowledge Sources / A. A Priori Knowledge / 6. A Priori from Reason
To achieve pure knowledge, we must get rid of the body and contemplate things with the soul [Plato]
14. Science / D. Explanation / 2. Types of Explanation / g. Causal explanations
To investigate the causes of things, study what is best for them [Plato]
15. Nature of Minds / A. Nature of Mind / 8. Brain
Do we think and experience with blood, air or fire, or could it be our brain? [Plato]
16. Persons / D. Continuity of the Self / 1. Identity and the Self
One soul can't be more or less of a soul than another [Plato]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / c. Ethical intuitionism
The forefather of modern intuitionism is Richard Price [Price,R, by Dancy,J]
22. Metaethics / C. The Good / 3. Pleasure / e. Role of pleasure
It is a mistake to think that the most violent pleasure or pain is therefore the truest reality [Plato]
23. Ethics / C. Virtue Theory / 4. External Goods / c. Wealth
War aims at the acquisition of wealth, because we are enslaved to the body [Plato]
26. Natural Theory / C. Causation / 2. Types of cause
Fancy being unable to distinguish a cause from its necessary background conditions! [Plato]
27. Natural Reality / E. Cosmology / 1. Cosmology
If the Earth is spherical and in the centre, it is kept in place by universal symmetry, not by force [Plato]
29. Religion / D. Religious Issues / 2. Immortality / a. Immortality
Whether the soul pre-exists our body depends on whether it contains the ultimate standard of reality [Plato]