16 ideas
| 8766 | In much wisdom is much grief [Anon (Ecc)] |
| 8767 | Sorrow is better than laughter [Anon (Ecc)] |
| 7494 | Laughter is mad; of mirth, what doeth it? [Anon (Ecc)] |
| 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] |
| 16669 | Everything that exists is either a being, or some mode of a being [Malebranche] |
| 8765 | All is vanity, saith the Preacher [Anon (Ecc)] |
| 8768 | Books are endless, and study is wearisome [Anon (Ecc)] |
| 2594 | A true cause must involve a necessary connection between cause and effect [Malebranche] |
| 12726 | In a true cause we see a necessary connection [Malebranche] |