Seneca explains how it is that humanity was able to deduce the Good and then he spends quite a bit of the letter providing examples of the sage and what it is we should be striving for.
He briefly re-states that he sees little difference between the Good and being honorable.
only the honourable can be good; also, the honourable is necessarily good. I hold it superfluous to add the distinction between these two qualities, inasmuch as I have mentioned it so many times. But I shall say this one thing – that we regard nothing as good which can be put to wrong use by any person. And you see for yourself to what wrong uses many men put their riches, their high position, or their physical powers.
We came to learn of the Good by observation. We observed the body and applied similar reasoning to the mind.
We understood what bodily health was: and from this basis we deduced the existence of a certain mental health also. We knew, too, bodily strength, and from this basis we inferred the existence of mental sturdiness. Kindly deeds, humane deeds, brave deeds, had at times amazed us; so we began to admire them as if they were perfect.
Being disposed to recognize greatness, we observed what was great about the characteristics of certain people.
Nature bids us amplify praiseworthy things: everyone exalts renown beyond the truth. And thus from such deeds we deduced the conception of some great good.
He provides an example;:
Fabricius rejected King Pyrrhus's gold, deeming it greater than a king's crown to be able to scorn a king's money. Fabricius also, when the royal physician promised to give his master poison, warned Pyrrhus to beware of a plot. The selfsame man had the resolution to refuse either to be won over by gold or to win by poison. So we admired the hero, who could not be moved by the promises of the king or against the king, who held fast to a noble ideal.
Deeds of people, as we have observed them, reveal the Good.
But we have to be quite discerning when it comes to identifying excellence of soul.
vices which are next-door to virtues; and even that which is lost and debased can resemble that which is upright.
Carelessness looks like ease, and rashness like bravery. This resemblance has forced us to watch carefully and to distinguish between things which are by outward appearance closely connected, but which actually are very much at odds with one another.
Then he details, in many ways, what the wise human looks like:
we have marked another man who is kind to his friends and restrained towards his enemies, who carries on his political and his personal business with scrupulous devotion, not lacking in longsuffering where there is anything that must be endured, and not lacking in prudence when action is to be taken. We have marked him giving with lavish hand when it was his duty to make a payment, and, when he had to toil, striving resolutely and lightening his bodily weariness by his resolution. Besides, he has always been the same, consistent in all his actions, not only sound in his judgment but trained by habit to such an extent that he not only can act rightly, but cannot help acting rightly. We have formed the conception that in such a man perfect virtue exists.
We have separated this perfect virtue into its several parts. The desires had to be reined in, fear to be suppressed, proper actions to be arranged, debts to be paid; we therefore included self-restraint, bravery, prudence, and justice – assigning to each quality its special function. How then have we formed the conception of virtue? Virtue has been manifested to us by this man's order, propriety, steadfastness, absolute harmony of action, and a greatness of soul that rises superior to everything. Thence has been derived our conception of the happy life, which flows along with steady course, completely under its own control. How then did we discover this fact? I will tell you: that perfect man, who has attained virtue, never cursed his luck, and never received the results of chance with dejection; he believed that he was citizen and soldier of the universe, accepting his tasks as if they were his orders. Whatever happened, he did not spurn it, as if it were evil and borne in upon him by hazard; he accepted it as if it were assigned to be his duty. "Whatever this may be," he says, "it is my lot; it is rough and it is hard, but I must work diligently at the task."
Necessarily, therefore, the man has shown himself great who has never grieved in evil days and never bewailed his destiny; he has given a clear conception of himself to many men; he has shone forth like a light in the darkness and has turned towards himself the thoughts of all men, because he was gentle and calm and equally compliant with the orders of man and of God. He possessed perfection of soul, developed to its highest capabilities, inferior only to the mind of God – from whom a part flows down even into this heart of a mortal. But this heart is never more divine than when it reflects upon its mortality, and understands that man was born for the purpose of fulfilling his life, and that the body is not a permanent dwelling, but a sort of inn (with a brief sojourn at that) which is to be left behind when one perceives that one is a burden to the host. The greatest proof, as I maintain, my dear Lucilius, that the soul proceeds from loftier heights, is if it judges its present situation lowly and narrow, and is not afraid to depart. For he who remembers whence he has come knows whither he is to depart.
We are merely passing though this life, borrowing the things which should be indifferent to us - our body, possessions, husband, wife, children, career, etc. What we are to demonstrate is duty and honorable use of these indifferents and circumstances. We ought not to get hung up on mortality, but "we [are to] set eternity before our eyes." Therefore,
the noble soul, knowing its better nature, while taking care to conduct itself honourably and seriously at the post of duty where it is placed, counts none of these extraneous objects as its own, but uses them as if they were a loan, like a foreign visitor hastening on his way.
The noble soul is steadfast, constant. "It is indeed consistency that abides; false things do not last."
Whereas, "The greatest proof of an evil mind is unsteadiness, and continued wavering between pretence of virtue and love of vice."
it is a great role – to play the role of one man. But nobody can be one person except the wise man; the rest of us often shift our masks.
force yourself to maintain to the very end of life's drama the character which you assumed at the beginning. See to it that men be able to praise you; if not, let them at least identify you.