Combining Texts

All the ideas for 'What is Logic?st1=Ian Hacking', 'Rule Utilitarianism and Euthanasia' and 'Of the Laws of Ecclesiastical Polity'

expand these ideas     |    start again     |     specify just one area for these texts

19 ideas

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]
23. Ethics / E. Utilitarianism / 2. Ideal of Pleasure
20883 Modern utilitarians value knowledge, friendship, autonomy, and achievement, as well as pleasure [Hooker,B]
23. Ethics / E. Utilitarianism / 5. Rule Utilitarianism
20884 Rule-utilitarians prevent things like torture, even on rare occasions when it seems best [Hooker,B]
25. Social Practice / C. Rights / 1. Basis of Rights
19896 It is not a law if not endorsed by the public [Hooker,R]
25. Social Practice / D. Justice / 2. The Law / b. Rule of law
19891 Rule of law is superior to autonomy, because citizens can see what is expected [Hooker,R]
25. Social Practice / D. Justice / 2. The Law / c. Natural law
19897 Human laws must accord with the general laws of Nature [Hooker,R]
25. Social Practice / F. Life Issues / 2. Euthanasia
20885 Euthanasia is active or passive, and voluntary, non-voluntary or involuntary [Hooker,B]
20882 Euthanasia may not involve killing, so it is 'killing or not saving, out of concern for that person' [Hooker,B]
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / c. Essence and laws
17005 Natural things observe certain laws, and things cannot do otherwise if they retain their forms [Hooker,R]