4. But this science, this Dialectic essential to all the three classes alike, what, in sum, is it?
It is the Method, or Discipline, that brings with it the power of pronouncing with final truth upon the nature and relation of things- what each is, how it differs from others, what common quality all have, to what Kind each belongs and in what rank each stands in its Kind and whether its Being is Real-Being, and how many Beings there are, and how many non-Beings to be distinguished from Beings.
Dialectic treats also of the Good and the not-Good, and of the particulars that fall under each, and of what is the Eternal and what the not Eternal- and of these, it must be understood, not by seeming-knowledge ["sense-knowledge"] but with authentic science.
All this accomplished, it gives up its touring of the realm of sense and settles down in the Intellectual Kosmos and there plies its own peculiar Act: it has abandoned all the realm of deceit and falsity, and pastures the Soul in the "Meadows of Truth": it employs the Platonic division to the discernment of the Ideal-Forms, of the Authentic-Existence and of the First-Kinds [or Categories of Being]: it establishes, in the light of Intellection, the unity there is in all that issues from these Firsts, until it has traversed the entire Intellectual Realm: then, resolving the unity into the particulars once more, it returns to the point from which it starts.
Now rests: instructed and satisfied as to the Being in that sphere, it is no longer busy about many things: it has arrived at Unity and it contemplates: it leaves to another science all that coil of premisses and conclusions called the art of reasoning, much as it leaves the art of writing: some of the matter of logic, no doubt, it considers necessary- to clear the ground- but it makes itself the judge, here as in everything else; where it sees use, it uses; anything it finds superfluous, it leaves to whatever department of learning or practice may turn that matter to account.