Epitome from Nagy 2015 §104:
Point 1. The ability of Menelaos to read the mind of Agamemnon indicates a special meaning for the adjective automatos here. On the one hand, if Menelaos comes to the feast ‘on his own’, then we can expect his mind to be ‘operating by itself’—which is the meaning built into automatos as a compounding of the element auto- ‘self’ with the element ma-t-, derived from the root *men-/*mn- meaning ‘mind’. So, Menelaos has a mind of his own. On the other hand, something unexpected is going on here: this mind of Menelaos, exceptionally, can read the mind of the brother, and so automatos in this context means not only ‘having a mind of his own’ but also ‘having the same mind’ as the brother has. In terms of this interpretation, Agamemnon and Menelaos have the same mind because they share their own selves with each other. We can find mythological patterns of twin-like behavior in Homeric descriptions of Agamemnon and Menelaos, and these patterns affect even their thinking. See Frame 2009:177, with a further reference at pp. 72–73 n. 156. More from Frame pp. 209–215: Also, Menelaos in the Iliad consistently fails to take the initiative whenever he undertakes an activity together with his brother. In such situations, Menelaos is recessive in his twinned thinking, while Agamemnon is dominant.
Point 2. There is an allusion in Plato Symposium 174b-d to the wording here in I.02.408. And, on the basis of Athenaeus 1.8a, we can reconstruct a relevant proverb, to which Plato’s text is also alluding. This proverb can be reconstructed as αὐτόματοι δ’ ἀγαθοὶ ἀγαθῶν ἐπὶ δαῖτας ἴασι ‘automatically do the noble go to the feasts of the noble’. In such a context, I add, not only does each noble person have ‘a mind of his own’: that mind is also the ‘same’ mind that the other noble persons have. The point is, ‘like-minded’ or ‘same-minded’ people congregate with each other automatically at dinners.