Letters 90.30

It is my opinion that the wise man has not withdrawn himself, as Posidonius thinks, from those arts which we were discussing, but that he never took them up at all. For he would have judged that nothing was worth discovering that he would not afterwards judge to be worth using always. He would not take up things which would have to be laid aside.

Seneca, Letters to Lucilius 90.30, translated by Richard Mott Gummere