Seneca, Moral Epistle 13.16-17
But now I will bring my letter to the end, if I give it its own seal, by which I mean I have commended some other great passage to be offered to you. “Among other faults, foolishness has this too: to always be about to start living.”
Consider what this line means, best of men, Lucilius, and you may understand how gross that lightness of men is when they trace out new foundations daily, beginning new projects even as they are leaving. Just think about some individual examples and old men will occur to you who are readying themselves for office, for journeys, for new business. What is more disgusting than an old man just beginning to live?
I should not include the author of this saying, except that this once is rather unknown and not among the common sayings of Epicurus, which allows me to praise it and take it as my own. Good bye!”
Sed iam finem epistulae faciam, si illi signum suum inpressero, id est aliquam magnificam vocem perferendam ad te mandavero. “Inter cetera mala hoc quoque habet stultitia: semper incipit vivere.” Considera quid vox ista significet, Lucili virorum optime, et intelleges, quam foeda sit hominum levitas cotidie nova vitae fundamenta ponentium, novas spes etiam in exitu inchoantium. Circumspice tecum singulos; occurrent tibi senes, qui se cum maxime ad ambitionem, ad peregrinationes, ad negotiandum parent. Quid est autem turpius quam senex vivere incipiens? Non adicerem auctorem huic voci, nisi esset secretior nec inter vulgata Epicuri dicta, quae mihi et laudare et adoptare permisi. Vale.
I am pretty sure Seneca is objecting not to the elderly making new starts but to people being so heedless of their lives as to only just start important things in old age. I am not quite sure Seneca would pass a Solon test.