Seneca,
The discussion of virtue is one which is interesting. It’s difficult sometimes to grok the concept. Like your example of a household or person being dyed in the quality of virtue, our modern conception of virtue is dyed in the Abrahamic context of the previous two millennia.
The Stoic position of a hard binary between virtue and vice, with no admission of progress is a tough hurdle. It also seems to belie the experience of most folks. We can see changes in our thinking, our actions, our intent. We can see how we handle impressions differently. Yet, this is no progress?
We can see ourselves renouncing the apparent goods of the world, with our attentions focused on what’s “up to us.” Yet, this is no progress?
I see your point that what is perfect cannot be made better, and if better occurs, it’s because some defect was present — but here eve we see a change towards the good. Why not call this progress?
The lack of progress produces a sense of urgency, but the non-Sage sometimes likes gold stars for good work, and a pat on the end. Of course, the Sage would not need these things…
Farewell.
I also read this letter recently—it’s worth noting that Marcus also uses the metaphor of “dyeing cloth” in in Meditations, 5.16.