15 ideas
| 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] |
| 16740 | A power is not a cause, but an aptitude for a cause [Zabarella] |
| 11993 | Jones may cease to exist without some simple property, but that doesn't make it essential [Kung] |
| 11997 | A property may belong essentially to one thing and contingently to another [Kung] |
| 11992 | Aristotelian essences underlie a thing's existence, explain it, and must belong to it [Kung] |
| 11995 | Some peripheral properties are explained by essential ones, but don't themselves explain properties [Kung] |
| 11996 | Some non-essential properties may explain more than essential-but-peripheral ones do [Kung] |
| 16571 | Prime matter is exceptionally obscure [Zabarella] |