Proclus, Theologia Platonica; Michael Psellos

For before such a cause, arguments are wandering; the way of life of the rulers and cosmic powers is difficult, fragmentary, and mindless for those established within it. But what is truly proper in these matters is that one should not be unlearned in natural science and the multiform opinions concerning it; how the world and living beings, by searching out the causes of existing things, might more easily traverse the nature of the primary-working hypostases and the maturity of needs; not indeed whatever these things might be that occur among those philosophizing on truth; nor let him be left behind by the paths of contradiction and the branches of learning within them; except for those through which we more reasonably come to know our own essence.

Observing these things for this reason, and participating in the discriminative power of all things, through the ruling mind—and in magnitude through its own excellent activities and intellection of the powers of bodies—he is released into the whole contemplation of beings, so that he may be wondrously guided by the divine and blessed doctrines. Having set the soul’s reason upon the erotic starting-line and vivifying it within, though he was once uninitiated in love, yet having received the apprehension of this contemplation, "he did not know," I said, as the divine Plato says. Having been trained in the knowledge of sensible things through every age, and having awakened the intelligible eye toward that truly ruling power—the stable, unmoved, and secure element of the knowledge of divine things—and being persuaded to hold nothing foreign toward his true self except through seeing clearly, he becomes a stranger to discursive thought, looking away toward the divine light by the power of his own life.

As he says, then, having at once put on such a garment and a form of stillness, such as befits the leader thus adorned—for as he says, the divine one says this to Socrates himself. The hypothesis, then, being so great and an abyss of the arguments concerning it, is of such a kind; and such is the aim of the mathematical sciences toward it. Such things, as they are, are clear to me as well. But before I begin the guidance of the matters set before us, I wish to speak about this same theological path, and those who possess it; and which of the ancients he establishes as doctrine, and which are to be rejected within the theological type.