The highest science
Apologies for the hiatus – I’ve been moving from Oxford from Cambridge, and the very stimulating Southern Association for Ancient Philosophy annual conference in Cambridge also intervened.
Once happy outcome of the conference: my attention was adverted by Sarah Broadie to a very useful article on EN X.9 called “The development of Aristotle’s political philosophy and the concept of nature” , which begins with a quote from Aristotle’s lost Protrepticus, an exhortation to philosophy written, we think, while he was still at the Academy. My interest piqued, I inquired further, and it seems that as far as ‘lost’ works go, there’s a good deal of material from the Protrepticus that survives. The ongoing reconstruction of the Protrepticus by D.S. Hutchinson and M. Johnson (see their website) follows along the lines of earlier work by Bywater, Jaeger, Gadamer (yes, that Gadamer!), and Düring — by mining the works of Iamblichus, who, as we can tell from his use of Plato, quoted (i.e., by our standards, plagiarised) liberally and often verbatim from his predecessors. The unmistakably Aristotelian air of several chapters of Iamblichus’ own Protrepticus leads to the natural conclusion that much of Aristotle’s own exhortation may be extracted.
Reading through a bit of this material, one passage caught my eye especially. For it is an unmistakably Platonic sentiment – that the highest science is philosophy – cast in roughly Aristotelian terms.
“Furthermore, there is a difference between the kinds of knowledge that produce each of the things of which we want to have more and more in our way of life, and the kinds of knowledge that make use of these kinds of knowledge, and the ones that give service are different from the others that issue orders; and in these as it were more commanding kinds of knowledge exists what is good in the strict sense.  If, then, only that kind of knowledge which does have correctness of judgment, and does use reason, and observes the good as a whole — that is to say, philosophy — is naturally capable of using all of them and issuing orders, by all means one ought to do philosophy, since only philosophy includes within itself this correct judgment and this intelligence to issue orders without errors.” (Iamblichus, Protrepticus 37.11-22, trans. Hutchinson & Johnson)
ἔτι τοίνυν ἄλλαι μέν εἰσιν αἱ ποιοῦσαι ἕκαστον τῶν ἐν τῷ βίῳ πλεονεκτημάτων ἐπιστῆμαι, ἄλλαι δὲ αἱ χρώμεναι ταύταις, καὶ ἄλλαι μὲν αἱ ὑπηρετοῦσαι, ἕτεραι δὲ αἱ ἐπιτάττουσαι, ἐν αἷς ἐστιν ὡς ἂν ἡγεμονικωτέραις ὑπαρχούσαις τὸ κυρίως ὂν ἀγαθόν. εἰ τοίνυν μόνη ἡ τοῦ κρίνειν ἔχουσα τὴν ὀρθότητα καὶ ἡ τῷ λόγῳ χρωμένη καὶ ἡ τὸ ὅλον ἀγαθὸν θεωροῦσα, ἥτις ἐστὶ φιλοσοφία, χρῆσθαι πᾶσι καὶ ἐπιτάττειν κατὰ φύσιν δύναται, φιλοσοφητέον ἐκ παντὸς τρόπου, ὡς μόνης φιλοσοφίας τὴν ὀρθὴν κρίσιν καὶ τὴν ἀναμάρτητον ἐπιτακτικὴν φρόνησιν ἐν ἑαυτῇ περιεχούσης. (Düring, fr. 9)
Certainly there is little here that could not be found in Plato’s Sophist, where the Visitor distinguishes and ranks the various kinds of science (253a-259e). The conclusion there is that the highest, kingly science is both theoretical and arranges all the others . In fact, it’s only in the very last word of the quote from Iamblichus that we find (I feel) a distinct echo  of the doctrine of EN I.1-2, where the highest science, political science (politikê), is the one whose end comprehends (periechoi, 1094b6) the ends of the other sciences. We find a similar use in Politics I.1, where the political community is the most comprehensive community.
What I find particularly engaging in this comparison is that Aristotle in the EN seems both to turn away from Plato’s and his earlier conviction that the highest science is theoretical (whereas we find in the last chapter of the EN that politikê requires practical experience), while nevertheless turning back, in a way, to Plato’s formulation in the Sophist of this science as the kingly or political one. I have a bit more to say about this – on the relation of political science to practical wisdom (phronêsis) in EN VI.8 and the relation of practical to theoretical wisdom (sophia) at the very end of Book VI – but I think I’ll leave it there.
 von Fritz, K. and Kapp, E.  “The development of Aristotle’s political philosophy and the concept of nature”, in J. Barnes, et. al. (eds.), Articles on Aristotle Vol. 2, (Duckworth 1977).
 See this section of the Stanford Encyclopedia of Philosophy entry on “Episteme and Techne” for a nice treatment of the development of Plato’s thought on this subject.
 The word does also appear in the Sophist, once in the middle of the section on sciences (253d). There, however, it’s used to describe forms subsuming other forms.