Seneca

“ With them you may class men whose dull nature and want of self-knowledge reduces them to the level of cattle, mere animals: there is no difference between the one and the other, because the latter have no reason, while the former have only a corrupted form of it, crooked and cunning to their own hurt. For no one can be styled happy who is beyond the influence of truth: and consequently a happy life is unchangeable, and is founded upon a true and trustworthy discernment ”

“ V. Since I have begun to make my definitions without a too strict adherence to the letter, a man may be called "happy" who, thanks to reason, has ceased either to hope or to fear: but rocks also feel neither fear nor sadness, nor do cattle, yet no one would call those things happy which cannot comprehend what happiness is. ”