Letters 88.26

Moreover, each has its own limits; for the wise man investigates and learns the causes of natural phenomena, while the mathematician follows up and computes their numbers and their measurements. The wise man knows the laws by which the heavenly bodies persist, what powers belong to them, and what attributes; the astronomer merely notes their comings and goings, the rules which govern their settings and their risings, and the occasional periods during which they seem to stand still, although as a matter of fact no heavenly body can stand still.

Seneca, Letters to Lucilius 88.26, translated by Richard Mott Gummere