23 ideas
10775 | The axiom of choice now seems acceptable and obvious (if it is meaningful) [Tharp] |
10766 | Logic is either for demonstration, or for characterizing structures [Tharp] |
10767 | Elementary logic is complete, but cannot capture mathematics [Tharp] |
10769 | Second-order logic isn't provable, but will express set-theory and classic problems [Tharp] |
10762 | In sentential logic there is a simple proof that all truth functions can be reduced to 'not' and 'and' [Tharp] |
10776 | The main quantifiers extend 'and' and 'or' to infinite domains [Tharp] |
10774 | There are at least five unorthodox quantifiers that could be used [Tharp] |
10773 | The Löwenheim-Skolem property is a limitation (e.g. can't say there are uncountably many reals) [Tharp] |
10777 | Skolem mistakenly inferred that Cantor's conceptions were illusory [Tharp] |
10765 | Soundness would seem to be an essential requirement of a proof procedure [Tharp] |
10763 | Completeness and compactness together give axiomatizability [Tharp] |
10770 | If completeness fails there is no algorithm to list the valid formulas [Tharp] |
10771 | Compactness is important for major theories which have infinitely many axioms [Tharp] |
10772 | Compactness blocks infinite expansion, and admits non-standard models [Tharp] |
10764 | A complete logic has an effective enumeration of the valid formulas [Tharp] |
10768 | Effective enumeration might be proved but not specified, so it won't guarantee knowledge [Tharp] |
7006 | Observing irrelevant items supports both 'all x are y' and 'all x are non-y', revealing its absurdity [Schofield,J] |
2854 | Prescriptivism says 'ought' without commitment to act is insincere, or weakly used [Hooker,B] |
2856 | Universal moral judgements imply the Golden Rule ('do as you would be done by') [Hooker,B] |
20883 | Modern utilitarians value knowledge, friendship, autonomy, and achievement, as well as pleasure [Hooker,B] |
20884 | Rule-utilitarians prevent things like torture, even on rare occasions when it seems best [Hooker,B] |
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] |