Out of the crooked timber of humanity, no straight thing was ever made.--Kant
Quaere quid est virtus, et posce exemplar honesti.--Lucan (quoted by David Hume as epigraph to Treatise 3.)
Our bodies can betray us. The main ploy of Seneca’s eleventh Letter is to use the all-too-human-phenomenon of blushing to talk about the limits that nature and our natures put on any philosophical wisdom. Seneca relies on the idea that blushing cannot be controlled even if one has completed an training in philosophical emendation of the mind. One aim of such a course is a kind of self-mastery, that is, to be composed. Seneca uses blushing as a metaphor for all the ways in which there are limits to our abilities to control nature more generally. Ever since Bacon and Descartes this outlook has been on the defensive, but if we are really heading toward an era of Environmental disasters, recognizing limits may well return to favor before long even if there might be over-the-counter pills against blushing.
Above, I use the plural “our natures,” not just because in an earlier letter Seneca had already implied there are a variety of kinds of souls (recall), but also because in the eleventh letter Seneca insists that our characters are, in part, the product of varying natural endowments. This sheds some light on the point of the little mystery at the start the eleventh Letter. For, Seneca introduces a third party, Lucilus’s “friend,” but does not reveal his identity. Presumably this is the same “friend” that had acted as (postal) messenger between Lucilus and Seneca before (recall the third letter). This time Seneca reports a conversation he had with the unnamed friend, and it reveals something about the qualities desired in a philosophical apprentice. It seems the friend has also started a course in philosophical improvement in which Seneca judges that he has progressed.)
According to Seneca, Lucillus’ friend has a lot of spirit and understanding; he is also a bit impulsive, and blushes when caught , which is taken to be a sign of shame, or modesty [verecundiam]—a good thing in this kind of young. (Seneca is revealed as impulsive in Letter 6; maybe that's not so good?) Even without peaking at the rest of Seneca’s letter (or Plato or Williams on shame), a moment’s reflection suggests that the reason why this is a good sign is that despite his impulsiveness, the friend recognizes that he has fallen short of the right sort of (noble) norm or standard that he (perhaps initially implicitly) already accepts or longs for. That is to say, the unnamed friend’s spirit is oriented toward the right sort of object according to Seneca. (Recall Seneca’s treatment of the proper sort of love and the proper sort of true friendship.) So, in the eyes of Seneca, Lucilus’ friend has the right sort of constitution to be a candidate to become wise—and in this manner he is offered as an exemplar to Lucilus (and us). One wonders, of course, how Lucilus would have reacted to the praise about his friend, especially if this is the same friend about which he had expressed ambivalence in letter 3. For it is by no means obvious that Lucilus is similarly oriented toward the right sort of norms.
Either way, Seneca closes the letter with some advice adopted from Epicurus that is appropriate to Lucilus and the rest of us. We need to adopt a noble exemplar and keep it in front of our eyes throughout all our actions (Cf. preface to Spinoza's Ethics.) This character within is a spectator that evaluates our actions. (Seneca invokes the idea that this adopted spectator can function like a true friend that is generous to and strict with us.) We find here already fully fleshed out the idea of the impartial spectator that provides the psychological mechanism by which norms of good conduct are internalized in the form of an all knowing, respectable judge who is intimately familiar with us. (In fact, her familiarity is crucial so the exemplar needs to be somebody whose company is to be sought.) She does not merely judge us after the fact but in her (nearby presence) can prevent bad actions; she plays the dual role of conscience and revered impartial spectator by which we gain command over ourselves. She is, as Seneca says, the rule by which we straighten our crookedness.
But this does not exhaust the functions of the proper exemplar. Her proper authority over us allows the development of the soul’s holiness. By revering the proper chosen exemplar we become ourselves the source of reverence. So, paradoxically a letter that seems about the body’s surface phenomenon (blushing) ultimately is about the depth (recall letter 5 on psychic depth) that we can generate within ourselves in virtue of our internalized relationship with the right sort of other.