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2 ideas
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. |