Letters 76.26

I also said that if those things which dumb animals possess equally with man are goods, then dumb animals also will lead a happy life; which is of course impossible. One must endure all things in defence of that which is honourable; but this would not be necessary if there existed any other good besides that which is honourable.

Although this question was discussed by me pretty extensively in a previous letter, I have discussed it summarily and briefly run through the argument.

Seneca, Letters to Lucilius 76.26, translated by Richard Mott Gummere