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'. |
| 12729 | The cause of a change is not the real influence, but whatever gives a reason for the change [Leibniz] |
| Full Idea: That thing from whose state a reason for the changes is most readily provided is adjudged to be the cause. ...Causes are not derived from a real influence, but from the providing of a reason. | |
| From: Gottfried Leibniz (Specimen inventorum [1689], A6.4.1620), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 5 | |
| A reaction: Leibniz is not denying that there are real influences. He seems to be offering the thesis which I am pursuing, that the need for explanation is the crucial factor in shaping the structure of our metaphysics. |
| 7435 | Dispositions are second-order properties, the property of having some property [Jackson/Pargetter/Prior, by Armstrong] |
| Full Idea: It was proposed that dispositions are second-order properties of objects: the property of having some property. | |
| From: report of Jackson/Pargetter/Prior (Three theses about dispositions [1982]) by David M. Armstrong - Pref to new 'Materialist Theory' p.xvii | |
| A reaction: It seems more plausible to say that dispositions are first-order properties - that is, properties are dispositions, which are causal powers. A disposition to smoke is to have a causal power which leads to smoking. |