18 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] |
10928 | Maybe we can quantify modally if the objects are intensional, but it seems unlikely [Quine] |
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] |
10925 | Failure of substitutivity shows that a personal name is not purely referential [Quine] |
10926 | Quantifying into referentially opaque contexts often produces nonsense [Quine] |
13852 | Axioms are ω-incomplete if the instances are all derivable, but the universal quantification isn't [Engelbretsen/Sayward] |
10930 | Quantification into modal contexts requires objects to have an essence [Quine] |
14645 | To be necessarily greater than 7 is not a trait of 7, but depends on how 7 is referred to [Quine] |
9201 | Whether 9 is necessarily greater than 7 depends on how '9' is described [Quine, by Fine,K] |
10927 | Necessity only applies to objects if they are distinctively specified [Quine] |
9203 | We can't quantify in modal contexts, because the modality depends on descriptions, not objects [Quine, by Fine,K] |
467 | A virtue is a combination of intelligence, strength and luck [Ion] |
10931 | We can't say 'necessarily if x is in water then x dissolves' if we can't quantify modally [Quine] |