21 ideas
19740 | A very hungry man cannot choose between equidistant piles of food [Aristotle] |
9193 | ZF set theory has variables which range over sets, 'equals' and 'member', and extensionality [Dummett] |
9194 | The main alternative to ZF is one which includes looser classes as well as sets [Dummett] |
9195 | Intuitionists reject excluded middle, not for a third value, but for possibility of proof [Dummett] |
9186 | First-order logic concerns objects; second-order adds properties, kinds, relations and functions [Dummett] |
9187 | Logical truths and inference are characterized either syntactically or semantically [Dummett] |
9191 | Ordinals seem more basic than cardinals, since we count objects in sequence [Dummett] |
9192 | The number 4 has different positions in the naturals and the wholes, with the same structure [Dummett] |
398 | Each thing that has a function is for the sake of that function [Aristotle] |
13304 | Learned men gain more in one day than others do in a lifetime [Posidonius] |
394 | An unworn sandal is in vain, but nothing in nature is in vain [Aristotle] |
396 | There has to be some goal, and not just movement to infinity [Aristotle] |
16102 | Aether moves in circles and is imperishable; the four elements perish, and move in straight lines [Aristotle, by Gill,ML] |
17463 | An element is what bodies are analysed into, and won't itself divide into something else [Aristotle] |
399 | If the more you raise some earth the faster it moves, why does the whole earth not move? [Aristotle] |
20918 | Void is a kind of place, so it can't explain place [Aristotle] |
20820 | Time is an interval of motion, or the measure of speed [Posidonius, by Stobaeus] |
403 | The earth must be round and of limited size, because moving north or south makes different stars visible [Aristotle] |
402 | The Earth must be spherical, because it casts a convex shadow on the moon [Aristotle] |
1498 | Everyone agrees that the world had a beginning, but thinkers disagree over whether it will end [Aristotle] |
395 | It seems possible that there exists a limited number of other worlds apart from this one [Aristotle] |