29 ideas
| 22271 | Aristotle was the first to use schematic letters in logic [Aristotle, by Potter] |
| 11060 | Aristotelian syllogisms are three-part, subject-predicate, existentially committed, with laws of thought [Aristotle, by Hanna] |
| 18909 | Aristotelian sentences are made up by one of four 'formative' connectors [Aristotle, by Engelbretsen] |
| 8080 | Aristotelian identified 256 possible syllogisms, saying that 19 are valid [Aristotle, by Devlin] |
| 13912 | Aristotle replaced Plato's noun-verb form with unions of pairs of terms by one of four 'copulae' [Aristotle, by Engelbretsen/Sayward] |
| 8071 | Aristotle listed nineteen valid syllogisms (though a few of them were wrong) [Aristotle, by Devlin] |
| 13819 | Aristotle's said some Fs are G or some Fs are not G, forgetting that there might be no Fs [Bostock on Aristotle] |
| 9403 | There are three different deductions for actual terms, necessary terms and possible terms [Aristotle] |
| 13010 | In order to select the logic justified by experience, we would need to use a lot of logic [Boghossian on Quine] |
| 9002 | Elementary logic requires truth-functions, quantifiers (and variables), identity, and also sets of variables [Quine] |
| 13681 | Logical consequence is marked by being preserved under all nonlogical substitutions [Quine, by Sider] |
| 11148 | Deduction is when we suppose one thing, and another necessarily follows [Aristotle] |
| 18896 | Aristotle places terms at opposite ends, joined by a quantified copula [Aristotle, by Sommers] |
| 13829 | If logical truths essentially depend on logical constants, we had better define the latter [Hacking on Quine] |
| 3300 | Aristotle's logic is based on the subject/predicate distinction, which leads him to substances and properties [Aristotle, by Benardete,JA] |
| 11149 | Affirming/denying sentences are universal, particular, or indeterminate [Aristotle] |
| 8079 | Aristotelian logic has two quantifiers of the subject ('all' and 'some') [Aristotle, by Devlin] |
| 9003 | Set theory was struggling with higher infinities, when new paradoxes made it baffling [Quine] |
| 9004 | If set theory is not actually a branch of logic, then Frege's derivation of arithmetic would not be from logic [Quine] |
| 9006 | Commitment to universals is as arbitrary or pragmatic as the adoption of a new system of bookkeeping [Quine] |
| 14637 | Only individuals have essences, so numbers (as a higher type based on classes) lack them [McMichael] |
| 14636 | Essences are the interesting necessary properties resulting from a thing's own peculiar nature [McMichael] |
| 14640 | Maybe essential properties have to be intrinsic, as well as necessary? [McMichael] |
| 14638 | Essentialism is false, because it implies the existence of necessary singular propositions [McMichael] |
| 14641 | A deduction is necessary if the major (but not the minor) premise is also necessary [Aristotle] |
| 9001 | Frege moved Kant's question about a priori synthetic to 'how is logical certainty possible?' [Quine] |
| 9005 | Examination of convention in the a priori begins to blur the distinction with empirical knowledge [Quine] |
| 18911 | Linguistic terms form a hierarchy, with higher terms predicable of increasing numbers of things [Aristotle, by Engelbretsen] |
| 14639 | Individuals enter into laws only through their general qualities and relations [McMichael] |