Among some commentators (e.g. Zuckert 2000, pp. 71-72) it has sometimes been argued that the difference between the Socratic and the Eleatic practice of philosophy lies in Socrates' attention to purposes. Thus, the argument goes, while the Stranger is busy creating purely "analytic" definitions of statesmanship, Socrates asks about the good to which statesmanship aims; and while the Eleatic casts around for "value-neutral" criteria for distinguishing sophist and philosopher, Socrates cuts to the nub of the matter by looking to the different motivations animating the practice of philosophy (the love of truth) and sophistry (a love of money, or reputation). The point is usually construed as a criticism of the Eleatic, and may support a view of the Eleatic dialogues in which the Eleatic is silently subverted: the failure of Platonic Eleatism serves to make Socratic philosophy all the more necessary.
It is true that the Stranger’s genealogies are unlike Socrates’ definitions of the arts in that they do not emphasize the ends to which the arts aim; the Stranger, for instance, in his definition of angling does not say why anybody would practice angling, or even explicitly say what is the end of angling, and in his last definition of sophistry he does not discuss why anybody would practice sophistry (since the references to money which were such an important part of the first four definitions of the sophist drop out in the sixth and seventh).
Nevertheless, these genealogies do incorporate the immediate function of the art (its ergon), a function which is naturally called an “immediate” purpose. What an art does – its ergon - is its end qua art, i.e., its function, though it may not be the ultimate purpose of the person practicing the art. The angler’s function, in this sense, is to hunt fish; and the function of sophistry is to seem wise, and these are things that the Stranger’s genealogies can inform us of. To ask why should anybody hunt fish or want to seem wise is to ask the question of the good of fish and that of wisdom, and this is a question that the Stranger certainly does not openly discuss, unlike Socrates.
That question, however, is implicit in the Stranger's depiction of a web of arts that are all connected in the Statesman. The good of an art can only be understood in reference to the function it plays in society; hence we cannot understand the problem of sophistry well until we come to understand the place it takes (or rather usurps) in the web of arts that constitute the city. In this sense the Stranger's and Socrates' methods seem more complementary than contradictory; we need not see in the Stranger's apparent lack of interest in the question of whether the sophist's motivations are good an actual disinterest in the goodness or badness of sophistry. On the contrary: as we learn (291aff), sophistry is genuinely dangerous to the polis insofar as it attempts to substitute for statesmanship. We might say that Socrates adopts the perspective of the individual, while the Stranger adopts the perspective of the "social system."