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'. |
| 20130 | It is absurd to think you can change your own essence, like a garment [Nietzsche] |
| Full Idea: Man is necessity down to his last fibre, and totally 'unfree', that is if one means by freedom the foolish demand to be able to change one's 'essentia' arbitrarily, like a garment. | |
| From: Friedrich Nietzsche (Philosophy in the Tragic Age of the Greeks [1873], p.7), quoted by Brian Leiter - Nietzsche On Morality 2 'Realism' | |
| A reaction: This is the big difference between the existentialism of Nietzsche and the more famous Sartrean approach, where the idea of being able to remake your essence is the most exciting and glamorous proposal. I'm with Nietzsche. |
| 8433 | There are few traces of an event before it happens, but many afterwards [Lewis, by Horwich] |
| Full Idea: Lewis claims that most events are over-determined by subsequent states of the world, but not by their history. That is, the future of every event contains many independent traces of its occurrence, with little prior indication that it would happen. | |
| From: report of David Lewis (Counterfactual Dependence and Time's Arrow [1979]) by Paul Horwich - Lewis's Programme p.209 | |
| A reaction: Lewis uses this asymmetry to deduce the direction of causation, and hence the direction of time. Most people (including me, I think) would prefer to use the axiomatic direction of time to deduce directions of causation. Lewis was very wicked. |