Life in accordance with intellect is best and pleasantest, since this, more than anything else, constitutes humanity.

The cultivation of the intellect is man's highest good and purest happiness

The most intelligent men, like the strongest, find their happiness where others would find only disaster: in the labyrinth, in being hard with themselves and with others, in effort; their delight is in self-mastery; in them asceticism becomes second nature, a necessity, an instinct. They regard a difficult task as a privilege; it is to them a recreation to play with burdens that would crush all others.

The man who makes everything that leads to happiness depends upon himself, and not upon other men, has adopted the very best plan for living happily. This is the man of moderation, the man of manly character and of wisdom.

Everything is estimated by the standard of its own good. The vine is valued for its productiveness and the flavour of its wine, the stag for his speed. We ask, with regard to beasts of burden, how sturdy of back they are; for their only use is to bear burdens. If a dog is to find the trail of a wild beast, keenness of scent is of first importance; if to catch his quarry, swiftness of foot; if to attack and harry it, courage. In each thing that quality should be best for which the thing is brought into being and by which it is judged. And what quality is best in man? It is reason; by virtue of reason he surpasses the animals, and is surpassed only by the gods. Perfect reason is therefore the good peculiar to man; all other qualities he shares in some degree with animals and plants. Man is strong; so is the lion. Man is comely; so is the peacock. Man is swift; so is the horse. I do not say that man is surpassed in all these qualities. I am not seeking to find that which is greatest in him, but that which is peculiarly his own. Man has body; so also have trees. Man has the power to act and to move at will; so have beasts and worms. Man has a voice; but how much louder is the voice of the dog, how much shriller that of the eagle, how much deeper that of the bull, how much sweeter and more melodious that of the nightingale! What then is peculiar to man? Reason. When this is right and has reached perfection, man's felicity is complete. Hence, if everything is praiseworthy and has arrived at the end intended by its nature, when it has brought its peculiar good to perfection, and if man's peculiar good is reason; then, if a man has brought his reason to perfection, he is praiseworthy and has readied the end suited to his nature. This perfect reason is called virtue, and is likewise that which is honourable.

Happy the man, of mortals happiest he,
Whose quiet mind from vain desires is free;
Whom neither hopes deceive, nor fears torment,
But lives at peace, within himself content;
In thought, or act, accountable to none
But to himself, and to the gods alone.

Purity is for man, next to life, the greatest good that parity is procured by the Law of Mazda to him who cleanses his own self with Good Thoughts, Words, and Deeds. (Extracts, p. 57)

[L]a felicité de l'homme consiste a vivre selon la raison.

The noblest mind the best contentment has.

men, in so far as they live in obedience to reason necessarily do only such things as are necessarily good for human nature, and consequently for each individual man.

He is best of all who of himself conceiveth all things; Good again is he too who can adopt a good suggestion; But whoso neither of himself conceiveth nor hearing from another Layeth it to heart; — he is a useless man. [Sidenote: V] But to return from this digression. Now of the Chief Good (i.e. of Happiness) men seem to form their notions from the different modes of life, as we might naturally expect: the many and most low conceive it to be pleasure, and hence they are content with the life of sensual enjoyment. For there are three lines of life which stand out prominently to view: that just mentioned, and the life in society, and, thirdly, the life of contemplation.

Human happiness consists in living according to reason.

As each man knows the life that fits him best,
The shape it makes in his soul, the tune, the tone

A prudent man, in order to secure his tranquility, will consult his natural disposition in the choice of his plan of life. If, for example, he be persuaded that he should be happier in a state of marriage than in celibacy, he ought to marry; but if he be convinced that matrimony would be an impediment to his happiness, he ought to remain single.