Combining Texts

All the ideas for 'Locke on Essences and Kinds', 'What is Logic?' and 'What is Good?'

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21 ideas

1. Philosophy / C. History of Philosophy / 3. Earlier European Philosophy / c. Later medieval philosophy
7823 Lucretius was rediscovered in 1417 [Grayling]
2. Reason / D. Definition / 3. Types of Definition
13838 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
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]
9. Objects / D. Essence of Objects / 13. Nominal Essence
15645 Nominal essence are the observable properties of things [Eagle]
15642 If kinds depend only on what can be observed, many underlying essences might produce the same kind [Eagle]
15643 Nominal essence mistakenly gives equal weight to all underlying properties that produce appearances [Eagle]
23. Ethics / C. Virtue Theory / 3. Virtues / e. Honour
7809 In an honour code shame is the supreme punishment, and revenge is a duty [Grayling]
25. Social Practice / F. Life Issues / 4. Suicide
7824 If suicide is lawful, but assisting suicide is unlawful, powerless people are denied their rights [Grayling]
26. Natural Theory / B. Natural Kinds / 4. Source of Kinds
15641 Kinds are fixed by the essential properties of things - the properties that make it that kind of thing [Eagle]
29. Religion / D. Religious Issues / 1. Religious Commitment / a. Religious Belief
7819 Religion gives answers, comforts, creates social order, and panders to superstition [Grayling]
29. Religion / D. Religious Issues / 2. Immortality / a. Immortality
7817 To make an afterlife appealing, this life has to be denigrated [Grayling]
7818 In Greek mythology only heroes can go to heaven [Grayling]