But it is not true that motion is of the essence of matter, if matter may be conceived of as at rest.] hence I infer that neither motion nor rest is essential to it, but motion, being an action, is the result of a cause of which rest is only the absence.
 Jean-Jacques Rousseau, Emile, or On Education (1762). copy citation

add
Author Jean-Jacques Rousseau
Source Emile, or On Education
Topic action absence
Date 1762
Language English
Reference
Note Translated by Barbara Foxley
Weblink http://www.gutenberg.org/cache/epub/5427/pg5427-images.html

Context

“I see it sometimes in motion, sometimes at rest, [Footnote: This repose is, if you prefer it, merely relative; but as we perceive more or less of motion, we may plainly conceive one of two extremes, which is rest; and we conceive it so clearly that we are even disposed to take for absolute rest what is only relative. But it is not true that motion is of the essence of matter, if matter may be conceived of as at rest.] hence I infer that neither motion nor rest is essential to it, but motion, being an action, is the result of a cause of which rest is only the absence. When, therefore, there is nothing acting upon matter it does not move, and for the very reason that rest and motion are indifferent to it, its natural state is a state of rest.
I perceive two sorts of motions of bodies, acquired motion and spontaneous or voluntary motion.” source