5 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'. |
| 22593 | Our sensation of light may not be the same as what produces the sensation [Descartes] |
| Full Idea: There can be a difference between our sensation of light and what is in the objects that produce that sensation in us. | |
| From: René Descartes (The World [1631]), quoted by Ian Dunt - How to be a Liberal 1 | |
| A reaction: Note only that they 'may' differ, and that he does not assert that they are entirely different. Secondary qualities give information, and are not just mental events. |
| 6017 | Nomos is king [Pindar] |
| Full Idea: Nomos is king. | |
| From: Pindar (poems [c.478 BCE], S 169), quoted by Thomas Nagel - The Philosophical Culture | |
| A reaction: This seems to be the earliest recorded shot in the nomos-physis wars (the debate among sophists about moral relativism). It sounds as if it carries the full relativist burden - that all that matters is what has been locally decreed. |
| 16569 | The Hot, Cold, Wet and Dry of the philosophers need themselves to be explained [Descartes] |
| Full Idea: If you find it strange that in explaining these elements I do not use the qualities called Hot, Cold, Wet and Dry - as the philosophers do - I shall say to you that these qualities themselves seem to me to need explanation. | |
| From: René Descartes (The World [1631], 9:25-6), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 1.3 | |
| A reaction: Nice. I take pushing the boundaries of explanation back (or down) to be the basic driving force of all human thought, in metaphysics as well as in physics. |
| 20964 | Descartes said there was conservation of 'quantity of motion' [Descartes, by Papineau] |
| Full Idea: Descartes incorporated the conservation of what he called 'quantity of motion', by which he meant mass times speed. | |
| From: report of René Descartes (The World [1631]) by David Papineau - Thinking about Consciousness App 2 | |
| A reaction: Mass times velocity is now called 'momentum'. Is this the first ever conservation law? There are now lots of them. |