17 ideas
| 7914 | To try to be wise all on one's own is folly [Rochefoucauld] |
| 13913 | The four 'perfect syllogisms' are called Barbara, Celarent, Darii and Ferio [Engelbretsen/Sayward] |
| 13914 | Syllogistic logic has one rule: what is affirmed/denied of wholes is affirmed/denied of their parts [Engelbretsen/Sayward] |
| 13915 | Syllogistic can't handle sentences with singular terms, or relational terms, or compound sentences [Engelbretsen/Sayward] |
| 13916 | Term logic uses expression letters and brackets, and '-' for negative terms, and '+' for compound terms [Engelbretsen/Sayward] |
| 13850 | In modern logic all formal validity can be characterised syntactically [Engelbretsen/Sayward] |
| 13849 | Classical logic rests on truth and models, where constructivist logic rests on defence and refutation [Engelbretsen/Sayward] |
| 13851 | Unlike most other signs, = cannot be eliminated [Engelbretsen/Sayward] |
| 13852 | Axioms are ω-incomplete if the instances are all derivable, but the universal quantification isn't [Engelbretsen/Sayward] |
| 12887 | A whole must have one characteristic, an internal relation, and a structure [Rescher/Oppenheim] |
| 7118 | La Rochefoucauld's idea of disguised self-love implies an unconscious mind [Rochefoucauld, by Sartre] |
| 7912 | Judging by effects, love looks more like hatred than friendship [Rochefoucauld] |
| 7915 | Supreme cleverness is knowledge of the real value of things [Rochefoucauld] |
| 7917 | Realising our future misery is a kind of happiness [Rochefoucauld] |
| 7913 | Virtue doesn't go far without the support of vanity [Rochefoucauld] |
| 7916 | True friendship is even rarer than true love [Rochefoucauld] |
| 9299 | We are bored by people to whom we ourselves are boring [Rochefoucauld] |