3 ideas
| 17743 | De Morgan introduced a 'universe of discourse', to replace Boole's universe of 'all things' [De Morgan, by Walicki] |
| Full Idea: In 1846 De Morgan introduced the enormously influential notion of a possibly arbitrary and stipulated 'universe of discourse'. It replaced Boole's original - and metaphysically a bit suspect - universe of 'all things'. | |
| From: report of Augustus De Morgan (works [1846]) by Michal Walicki - Introduction to Mathematical Logic History D.1.1 | |
| A reaction: This not only brings formal logic under control, but also reflects normal talk, because there is always an explicit or implicit domain of discourse when we talk. Of virtually any conversation, you can say what it is 'about'. |
| 8714 | Fictionalists say 2+2=4 is true in the way that 'Oliver Twist lived in London' is true [Field,H] |
| Full Idea: The fictionalist can say that the sense in which '2+2=4' is true is pretty much the same as the sense in which 'Oliver Twist lived in London' is true. They are true 'according to a well-known story', or 'according to standard mathematics'. | |
| From: Hartry Field (Realism, Mathematics and Modality [1989], 1.1.1), quoted by Michèle Friend - Introducing the Philosophy of Mathematics 6.3 | |
| A reaction: The roots of this idea are in Carnap. Fictionalism strikes me as brilliant, but poisonous in large doses. Novels can aspire to artistic truth, or to documentary truth. We invent a fiction, and nudge it slowly towards reality. |
| 7331 | A theory of meaning comes down to translating sentences into Fregean symbolic logic [Davidson, by Macey] |
| Full Idea: For a theory of meaning for a fragment of natural language, what Davidson requires, in effect, is that the sentences be translatable into the language of Frege's symbolic logic. | |
| From: report of Donald Davidson (In Defence of Convention T [1973]) by David Macey - Penguin Dictionary of Critical Theory | |
| A reaction: This assumes the adequacy of Fregean logic, which seems unlikely. Is this the culmination of Leibniz's dream of a fully logical language - so that anything that won't fit into our logical form is ruled (logical positivist style) as meaningless? |