“and to every action there is always an equal and opposite or contrary, reaction”

“eorum omnium actiones in se invicem”

“God without dominion, providence, and final causes, is nothing else but Fate and Nature. Blind metaphysical necessity, which is certainly the same always and everywhere, could produce no variety of things. All that diversity of natural things which we find suited to different times and places could arise from nothing but the ideas and will of a Being necessarily existing.”

“A Vulgar Mechanick can practice what he has been taught or seen done, but if he is in an error he knows not how to find it out and correct it, and if you put him out of his road he is at a stand. Whereas he that is able to reason nimbly and judiciously about figure, force, and motion, is never at rest till he gets over every rub.(from a letter dated 25 May, 1694)”

“What goes up must come down.”

“Los hombres construimos demasiados muros y no suficientes puentes.”

“If I have seen further it is by standing on the shoulders of Giants.”