He means that a sophist like Protagoras will teach superficially anything as wisdom for money; and that even a dialectician like Plato will write a dialogue, such as the Republic, nominally about justice, but really about all things from the generality of the form of good, instead of from appropriate moral principles; but that a primary philosopher selects as a definite subject all things as such without interfering with the special sciences of different things each in its kind (Met.
His vast learning was the result of a powerful memory and unwearied industry, and he lacked the creative imagination necessary to mould this material into new forms. He was a powerful debater, but his victories were those of a dialectician rather than a convincing reasoner, and in him depth of insight and conviction were ill replaced by the controversial violence characteristic of the age.
When brought before the emperor, Gerbert admitted his skill in all branches of the quadrivium, but lamented his comparative ignorance of logic. Eager to supply this deficiency he followed Lothair's ambassador Germanus, archdeacon of Reims, to that city, for the sake of studying under so famous a dialectician in the episcopal schools which were rising into reputation under Archbishop Adalbero (969-989).
Meanwhile, however, the truth about the Eudemian Ethics in general is that it was an earlier rudimentary sketch written by Aristotle, when he was still struggling, without quite succeeding, to get over Plato's view that there is one philosophical knowledge of universal good, by which not only the dialectician and mathematician must explain the being and becoming of the world, but also the individual and the statesman guide the life of man.