9 ideas
| 3340 | Von Neumann defines each number as the set of all smaller numbers [Neumann, by Blackburn] |
| Full Idea: Von Neumann defines each number as the set of all smaller numbers. | |
| From: report of John von Neumann (works [1935]) by Simon Blackburn - Oxford Dictionary of Philosophy p.280 |
| 3355 | Von Neumann wanted mathematical functions to replace sets [Neumann, by Benardete,JA] |
| Full Idea: Von Neumann suggested that functions be pressed into service to replace sets. | |
| From: report of John von Neumann (works [1935]) by José A. Benardete - Metaphysics: the logical approach Ch.23 |
| 22716 | Von Neumann defined ordinals as the set of all smaller ordinals [Neumann, by Poundstone] |
| Full Idea: At age twenty, Von Neumann devised the formal definition of ordinal numbers that is used today: an ordinal number is the set of all smaller ordinal numbers. | |
| From: report of John von Neumann (works [1935]) by William Poundstone - Prisoner's Dilemma 02 'Sturm' | |
| A reaction: I take this to be an example of an impredicative definition (not predicating something new), because it uses 'ordinal number' in the definition of ordinal number. I'm guessing the null set gets us started. |
| 23569 | The only just cause for a war is a wrong received [Vitoria] |
| Full Idea: There is a single and only just cause for commencing a war, namely, a wrong received. | |
| From: Francis de Vitoria (On the Law of War [1525], p.170), quoted by Michael Walzer - Just and Unjust Wars 04 | |
| A reaction: Walzer affirms this as one the principles of international law. In particular, mere differences of religion or politics cannot justify a war. The tricky bit is when the participants don't agree on the severity of the wrong. |
| 23601 | Leaders can only attack foreigners who have done wrong (as with their own subjects) [Vitoria] |
| Full Idea: A political leader cannot have greater authority over foreigners than over his own subjects; but he may not draw the sword against his own subjects unless they have done wrong; therefore he can only do so against foreigners in the same circumstances. | |
| From: Francis de Vitoria (On the Law of War [1525], p.303), quoted by Jeff McMahan - Killing in War 1.4 | |
| A reaction: The question would then be whether they have 'done some wrong' against this leader, or against some other people (such as their fellow citizens). That would be the 'intervention' justification. Are they engaged in the wrong, or responsible for it? |
| 23566 | Princes should not justify a war to their subjects, and doing so would undermine the state [Vitoria] |
| Full Idea: A prince is not able and ought not always to render reasons for the war to its subjects, and if the subjects cannot serve in the war except they be satisfied of its justice, the state would fall into grave peril. | |
| From: Francis de Vitoria (On the Law of War [1525], p.176), quoted by Michael Walzer - Just and Unjust Wars 03 | |
| A reaction: This medieval view depends entirely on the absolute sovereignty of princes, and confidence that princes are wise and innately just. No student of history should believe such wicked nonsense. |
| 23576 | Sacking a city is lawful if it motivates the attacking troops [Vitoria] |
| Full Idea: It is not unlawful to put a city to sack, if it is necessary for the conduct of the war …as a spur to the courage of the troops. | |
| From: Francis de Vitoria (On the Law of War [1525], p.184), quoted by Michael Walzer - Just and Unjust Wars 08 | |
| A reaction: Hideous. Presumably this would include raping the women. Could you motivate a football team in a similar way? Or to get your children to pass exams? |
| 13304 | Learned men gain more in one day than others do in a lifetime [Posidonius] |
| Full Idea: In a single day there lies open to men of learning more than there ever does to the unenlightened in the longest of lifetimes. | |
| From: Posidonius (fragments/reports [c.95 BCE]), quoted by Seneca the Younger - Letters from a Stoic 078 | |
| A reaction: These remarks endorsing the infinite superiority of the educated to the uneducated seem to have been popular in late antiquity. It tends to be the religions which discourage great learning, especially in their emphasis on a single book. |
| 20820 | Time is an interval of motion, or the measure of speed [Posidonius, by Stobaeus] |
| Full Idea: Posidonius defined time thus: it is an interval of motion, or the measure of speed and slowness. | |
| From: report of Posidonius (fragments/reports [c.95 BCE]) by John Stobaeus - Anthology 1.08.42 | |
| A reaction: Hm. Can we define motion or speed without alluding to time? Looks like we have to define them as a conjoined pair, which means we cannot fully understand either of them. |