display all the ideas for this combination of texts
3 ideas
| 16922 | Space must have three dimensions, because only three lines can meet at right angles [Kant] |
| Full Idea: That complete space …has three dimensions, and that space in general cannot have more, is built on the proposition that not more than three lines can intersect at right angles in a point. | |
| From: Immanuel Kant (Prolegomena to Any Future Metaphysic [1781], 285) | |
| A reaction: Modern geometry seems to move, via the algebra, to more than three dimensions, and then battles for an intuition of how that can be. I don't know how they would respond to Kant's challenge here. |
| 16921 | If all empirical sensation of bodies is removed, space and time are still left [Kant] |
| Full Idea: If everything empirical, namely what belongs to sensation, is taken away from the empirical intuition of bodies and their changes (motion), space and time are still left. | |
| From: Immanuel Kant (Prolegomena to Any Future Metaphysic [1781], 284) | |
| A reaction: This is an exercise in psychological abstraction, which doesn't sound like good evidence, though it is an interesting claim. Physicists want to hijack this debate, but I like Kant's idea. |
| 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. |