Cicero, De Finibus 5. 87
“For this reason we must examine whether or not it is possible for the study of the philosophers to bring us [happiness].”
Quare hoc videndum est, possitne nobis hoc ratio philosophorum dare.
Aristotle, Eudemian Ethics, 2.1 (1219a25)
“Let the work of the mind be the performance of life—and what this means is using life and being awake (for sleep is some kind of a rest and cessation of life). As a result, since the work of the mind and its virtue are identical, then the work of virtue is an earnest life.
This, then, is the complete good, which is itself happiness. For it is clear from what we have argued—as we said that happiness was the best thing; the goals and the greatest of the goods are in the mind, but aspects of the mind are either a state of being or an action—it is clear that, since an action is better than a state and the best action is better than the best state, that the performance of virtue is the greatest good of the mind. Happiness, then, is the action of a good mind.”
Ἔτι ἔστω ψυχῆς ἔργον τὸ ζῆν ποιεῖν, τοῦτοχρῆσις καὶ ἐγρήγορσις (ὁ γὰρ ὕπνος ἀργία τις καὶ ἡσυχία)· ὥστ᾿ ἐπεὶ τὸ ἔργον ἀνάγκη ἓν καὶ ταὐτὸ εἶναι τῆς ψυχῆς καὶ τῆς ἀρετῆς, ἔργον ἂν εἴη τῆς ἀρετῆς ζωὴ σπουδαία.
τοῦτ᾿ ἄρ᾿ ἐστὶ τὸ τέλεον ἀγαθόν, ὅπερ ἦν ἡ εὐδαιμονία. δῆλον δὲ ἐκ τῶν ὑποκειμένων (ἦν μὲν γὰρ ἡ εὐδαιμονία τὸ ἄριστον, τὰ δὲ τέλη ἐν ψυχῇ καὶ τὰ ἄριστα τῶν ἀγαθῶν, τὰ ἐν αὐτῇ δὲ ἢ ἕξις ἢ ἐνέργεια), ἐπεὶ βέλτιον ἡ ἐνέργεια τῆς διαθέσεως καὶ τῆς βελτίστης ἕξεως ἡ βελτίστη ἐνέργεια ἡ δ᾿ ἀρετὴ βελτίστη ἕξις, τὴν τῆς ἀρετῆς ἐνέργειαν τῆς ψυχῆς ἄριστον εἶναι. ἦν δὲ καὶ ἡ εὐδαιμονία τὸ ἄριστον· ἔστιν ἄρα ἡ εὐδαιμονία ψυχῆς ἀγαθῆς ἐνέργεια.
ψυχή: can be translated into English as “spirit” or “soul” instead of “mind”. I avoided the former to sidestep the implication that Aristotle is making some kind of a mystical argument; I avoided the latter because it has such strong religious associations in English.
Seneca De Beneficiis 22
“A just reason for happiness is seeing that a friend is happy—even better, is to make a friend happy.”
iusta enim causa laetitiae est laetum amicum videre, iustior fecisse