Tusculan Disputations 4 ¶35 — Cicero (on the Stoics)

Cicero (on the Stoics), Tusculan Disputations 4 ¶35

The man who attempts to set bounds to vice acts like one who should throw himself headlong from Leucate, persuaded that he could stop himself whenever he pleased. Now as that is impossible, so a perturbed and disordered mind cannot restrain itself and stop where it pleases. Certainly whatever is bad in its increase is bad in its birth. Now grief and all other perturbations are doubtless baneful in their progress, and have, therefore, no small share of evil at the beginning. For they go on of themselves when once they depart from reason, for every weakness is self-indulgent, and indiscreetly launches out and does not know where to stop. So that it makes no difference whether you approve of moderate perturbations of mind, or of moderate injustice, moderate cowardice, and moderate intemperance; for whoever prescribes bounds to vice admits a part of it, which, as it is odious of itself, becomes the more so as it stands on slippery ground, and being once set forward, glides on headlong and cannot by any means be stopped.