Combining Texts

All the ideas for 'Meno', 'What is Logic?' and 'Letter to Frege 29.12.1899'

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24 ideas

1. Philosophy / A. Wisdom / 1. Nature of Wisdom
1922 Spiritual qualities only become advantageous with the growth of wisdom [Plato]
2. Reason / D. Definition / 3. Types of Definition
13838 A decent modern definition should always imply a semantics [Hacking]
3. Truth / G. Axiomatic Truth / 1. Axiomatic Truth
15716 If axioms and their implications have no contradictions, they pass my criterion of truth and existence [Hilbert]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / d. Basic theorems of PL
13833 'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [Hacking]
13834 Gentzen's Cut Rule (or transitivity of deduction) is 'If A |- B and B |- C, then A |- C' [Hacking]
13835 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
13845 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
13840 First-order logic is the strongest complete compact theory with Löwenheim-Skolem [Hacking]
13844 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
13842 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
13837 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
13839 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
13843 If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking]
5. Theory of Logic / L. Paradox / 2. Aporiai
11259 How can you seek knowledge of something if you don't know it? [Plato]
11. Knowledge Aims / A. Knowledge / 3. Value of Knowledge
20219 True opinions only become really valuable when they are tied down by reasons [Plato]
12. Knowledge Sources / A. A Priori Knowledge / 3. Innate Knowledge / b. Recollection doctrine
5985 Seeking and learning are just recollection [Plato]
5986 The slave boy learns geometry from questioning, not teaching, so it is recollection [Plato]
13. Knowledge Criteria / A. Justification Problems / 1. Justification / b. Need for justification
1923 As a guide to action, true opinion is as good as knowledge [Plato]
13. Knowledge Criteria / D. Scepticism / 6. Scepticism Critique
1919 You don't need to learn what you know, and how do you seek for what you don't know? [Plato]
23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / d. Teaching virtue
1927 It seems that virtue is neither natural nor taught, but is a divine gift [Plato]
1913 Is virtue taught, or achieved by practice, or a natural aptitude, or what? [Plato]
1921 If virtue is a type of knowledge then it ought to be taught [Plato]
23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / j. Unity of virtue
1916 Even if virtues are many and various, they must have something in common to make them virtues [Plato]
1918 How can you know part of virtue without knowing the whole? [Plato]