23 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] |
17000 | We might fix identities for small particulars, but it is utopian to hope for such things [Kripke] |
11868 | A different piece of wood could have been used for that table; constitution isn't identity [Wiggins on Kripke] |
17044 | A relation can clearly be reflexive, and identity is the smallest reflexive relation [Kripke] |
16999 | A vague identity may seem intransitive, and we might want to talk of 'counterparts' [Kripke] |
17058 | What many people consider merely physically necessary I consider completely necessary [Kripke] |
4970 | What is often held to be mere physical necessity is actually metaphysical necessity [Kripke] |
17059 | Unicorns are vague, so no actual or possible creature could count as a unicorn [Kripke] |
4950 | Possible worlds are useful in set theory, but can be very misleading elsewhere [Kripke] |
17003 | Kaplan's 'Dthat' is a useful operator for transforming a description into a rigid designation [Kripke] |
9221 | The best known objection to counterparts is Kripke's, that Humphrey doesn't care if his counterpart wins [Kripke, by Sider] |
17052 | The a priori analytic truths involving fixing of reference are contingent [Kripke] |
4969 | I regard the mind-body problem as wide open, and extremely confusing [Kripke] |
3448 | Do new ideas increase the weight of the brain? [Dance] |
4956 | A description may fix a reference even when it is not true of its object [Kripke] |
17032 | Even if Gödel didn't produce his theorems, he's still called 'Gödel' [Kripke] |