I have been asking about you, and inquiring of everyone who comes from your part of the country, what you are doing, and where you are spending your time, and with whom. You cannot deceive me; for I am with you. Live just as if I were sure to get news of your doings, nay, as if I were sure to behold them. And I hear you ask, why do you take pleasure in learning those things which they have? There is nothing to hear, I do not know most of those I have named, I will ask what you are doing.
This is sound practice - to refrain from associating with men of different stamp and different aims. And I am indeed confident that you cannot be warped, that you will stick to your purpose, even though the crowd may surround and seek to distract you. What, then, is on my mind? I am not afraid lest they work a change in you; but I am afraid lest they may hinder your progress. And much harm is done even by one who holds you back, especially since life is so short; and we make it still shorter by our unsteadiness, by making ever fresh beginnings at life, now one and immediately another. We break up life into little bits, and fritter it away.--Seneca, Letter 32. Translated by Richard M. Gummere (with modifications)
Seneca here emulates the gossipy part of Socrates ( Theaetetus 143-5 and Socrates's interest in promising young men), but he goes beyond Socrates, I think by proposing himself as a kind of imaginary, impartial spectator to Lucilius. Rather than seeking out a diversity of opinions and lives, and choose what is best among them, Seneca encourages Lucilius to stick with the (properly!) like-minded, that is, to be sectarian.
Seneca treats temptations and distractions from the unalike and differentially oriented [dissimilibus et diversa cupientibus] as the cause of fresh starts. These are not mere speed-bumps on the path toward virtue, but rather [facientes initium] new beginnings (in the manner of a Monopoly card that tells you to go straight to jail and don't collect the cash for passing start). There is here an anxiety about permanent distortion [detorqueri mansurumque], that is, contamination. The brevity of life matters here not in order to live longer in time, but because each fresh start requires us to overcome serious obstacles such that none of us is in touch with ourselves [nemo sibi contigit]--Seneca, here anticipates recent self-help lingo.
But the point of this self-insulation under the watchful eyes of an imagined permanent guardian is to make one's mind steadfast [certa sit] in/by the understanding of truly good objects, and thereby (recall also) content with itself. Such a mind becomes/is one with the things so known. [See Seneca's, intellectis veris bonis, quae simul intellecta sunt possidentur.] This is a kind of effacement of individuality and the accompanying longing for novelty, so that that there is no need of added time. The inference to the last point may be obscure. But it's only obscure if one forgets that the content of the truly good objects are eternal goods. The happy mind is in touch with the eternal, divine part of self, which is, thus, simultaneously no individuated self at all.
It is notable that in this letter Seneca here returns to the brevity of the start of the Letters and simultaneously omits his usual rhetoric of sharing the insights of Epicurean as his own (and presented as part of a credit economy). (For those who doubt the significance of this, I break my practice of not peeking ahead by noting that the point is made explicit at the start of the very next letter.) This letter, thus, signals a fresh start in the enterprise of the Letters.
It is tempting to close here.
Even so, if one is focused on the mystical (even new-age) elements in Seneca's line of thought, it is easy to miss the harsh rejection of contemporary life. A notable example is the contemptuous [contemptum] rejection of the abundance Lucilius' parents would have wished for him. Presumably these would have wished worldly success, continuation of the family line (and property) or contribution to fatherland and its gods. Seneca's condemnation of society's fundamental ideologies extends to the thought that parents are deluded in what they wish for their children.
The refreshing element, it startles to this day, here is Seneca's unwillingness to play along with the saccharine aura that surrounds selfless, parental desire about the lives of their offspring. He recognizes that if society is rotten this is, in part, the product of systematic, parental cognitive error.
Once one grants Seneca's point, one may come to think the more dangerous thought that the social order may require a fresh start.