31 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] |
| 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] |
| 4975 | A thought can be split in many ways, so that different parts appear as subject or predicate [Frege] |
| 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] |
| 9949 | There is the concept, the object falling under it, and the extension (a set, which is also an object) [Frege, by George/Velleman] |
| 18995 | Frege mistakenly takes existence to be a property of concepts, instead of being about things [Frege, by Yablo] |
| 10317 | It is unclear whether Frege included qualities among his abstract objects [Frege, by Hale] |
| 7720 | Two things can only resemble one another in some respect, and that may reintroduce a universal [Lowe] |
| 10535 | Frege's 'objects' are both the referents of proper names, and what predicates are true or false of [Frege, by Dummett] |
| 7712 | On substances, Leibniz emphasises unity, Spinoza independence, Locke relations to qualities [Lowe] |
| 14641 | A deduction is necessary if the major (but not the minor) premise is also necessary [Aristotle] |
| 7710 | Perception is a mode of belief-acquisition, and does not involve sensation [Lowe] |
| 7711 | Science requires a causal theory - perception of an object must be an experience caused by the object [Lowe] |
| 18911 | Linguistic terms form a hierarchy, with higher terms predicable of increasing numbers of things [Aristotle, by Engelbretsen] |
| 7714 | Personal identity is a problem across time (diachronic) and at an instant (synchronic) [Lowe] |
| 7715 | Mentalese isn't a language, because it isn't conventional, or a means of public communication [Lowe] |
| 9839 | Frege equated the concepts under which an object falls with its properties [Frege, by Dummett] |
| 4973 | As I understand it, a concept is the meaning of a grammatical predicate [Frege] |
| 7722 | If meaning is mental pictures, explain "the cat (or dog!) is NOT on the mat" [Lowe] |
| 9167 | Frege felt that meanings must be public, so they are abstractions rather than mental entities [Frege, by Putnam] |
| 4974 | For all the multiplicity of languages, mankind has a common stock of thoughts [Frege] |