6 ideas
| 21558 | 'Predicative' norms are those which define a class [Russell] |
| Full Idea: Norms (containing one variable) which do not define classes I propose to call 'non-predicative'; those which do define classes I shall call 'predicative'. | |
| From: Bertrand Russell (Difficulties of Transfinite Numbers and Types [1905], p.141) |
| 21559 | We need rules for deciding which norms are predicative (unless none of them are) [Russell] |
| Full Idea: We need rules for deciding what norms are predicative and what are not, unless we adopt the view (which has much to recommend it) that no norms are predicative. ...[146] A predative propositional function is one which determines a class. | |
| From: Bertrand Russell (Difficulties of Transfinite Numbers and Types [1905], p.141) | |
| A reaction: He is referring to his 'no class' theory, which he favoured at that time. |
| 22363 | You have only begun to do real science when you can express it in numbers [Kelvin] |
| Full Idea: When you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of science, whatever the matter may be. | |
| From: Lord Kelvin (Wm Thomson) (works [1881]), quoted by Reiss,J/Spreger,J - Scientific Objectivity 4.1 | |
| A reaction: [Popular Lectures 1 p.73] Clearly the writer is a physicist! Astronomers discover objects, geologists discover structures, biologists reveal mechanisms. |
| 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. |
| 20644 | Energy has progressed from a mere formula, to a principle pervading all nature [Kelvin] |
| Full Idea: The name 'energy', first used by Thomas Young, has come into use after it was raised from a mere formula of mathematical dynamics to become a principle pervading all nature, and guiding every field of science. | |
| From: Lord Kelvin (Wm Thomson) (works [1881]), quoted by Peter Watson - Convergence 01 'Principle' | |
| A reaction: [bit compressed] As far as I can see energy behaves exactly as if it were a substance, like water conserved in rainfalls, and yet it isn't a stuff, and seems to result from a process of abstraction. I take it to be one of the biggest mysteries in physics. |
| 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. |