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] |
| 17807 | To study formal systems, look at the whole thing, and not just how it is constructed in steps [Curry] |
| 13852 | Axioms are ω-incomplete if the instances are all derivable, but the universal quantification isn't [Engelbretsen/Sayward] |
| 17806 | It is untenable that mathematics is general physical truths, because it needs infinity [Curry] |
| 17808 | Saying mathematics is logic is merely replacing one undefined term by another [Curry] |
| 3914 | Language arranges sensory experience to form a world-order [Whorf] |
| 3916 | Hopi consistently prefers verbs and events to nouns and things [Whorf] |
| 3917 | Scientific thought is essentially a specialised part of Indo-European languages [Whorf] |
| 3915 | The Hopi have no concept of time as something flowing from past to future [Whorf] |