Didascalicon, Book I (chapters 2-13): the origin of the arts and the division of philosophy
Chapter II. On the origin of the arts, and the perfection of the soul
Of all things to be desired, the first is wisdom, in which the form of the perfect good consists. Wisdom enlightens man that he may know himself, who was like the rest of creatures when he did not understand that he had been made above the rest. For the immortal mind, illumined by wisdom, looks back to its own beginning, and recognizes how unseemly it is for it to seek anything outside itself; what it is itself could have been enough for it. It is written on the tripod of Apollo, in Greek, “Know thyself”; for surely if man were not forgetful of his origin, he would recognize how much nothing everything is that is subject to change. A sentence approved among the philosophers is this: “The soul is said to be compacted from all the parts of nature.” And the Timaeus of Plato says: “From divisible and indivisible substance, mingled together, and likewise from the same and the different, and from a nature blended of both, by which the universe is signified, he formed the soul as a perfection.” For the soul takes in both the principles and what follows from them: for it comprehends by intelligence the invisible causes of things, and gathers by the impressions of the senses the visible forms of actual things; moving in twin orbits, it gathers up its motion, because whether it goes out through the senses to sensible things, or ascends through intelligence to invisible things, it draws the likenesses of things to itself and turns back on itself; and this is why the same mind, which is capable of all things, is fitted together out of every substance and nature, that it may present the figure of likeness. For it was a Pythagorean doctrine that “like is comprehended by like”; that is, that the rational soul, unless it were composed of all things, could in no way comprehend all things, as one says:
By earth we grasp the earthly, the ether by flames, moisture by the liquid, the breathable air by our own breath.
Yet we must not suppose that men most skilled in the whole of nature held this of a simple essence, as though it were extended by any quantity of parts; but in order to show more plainly its wonderful power, they said that it consists of all natures: not according to composition but according to the principle of composition. For this likeness to all things is not to be believed to come to the soul from elsewhere or from outside, but the soul itself takes it in itself and from itself by a certain native power and its own virtue. For as Varro says in the Periphysis: “Not all variety befalls things from outside, so that whatever is varied must either lose something it had or take on from outside something else and different that it did not have. We see that a wall, when the form of some image comes to it from outside, receives a likeness; but when the one who imprints presses a figure upon it, it begins to represent something else, not from within, but from its own power and natural aptitude.” So the mind, marked with the likeness of all things, is said to be all things, and to receive composition from all, containing them not integrally but virtually and potentially. And this is that dignity of our nature which all alike naturally have, but not all equally know. For the mind, lulled asleep by the passions of the body and drawn outside itself through sensible forms, has forgotten what it was, and because it remembers nothing else that it was, believes that nothing exists beyond what is seen. But it is restored by learning, that we may recognize our nature and learn not to seek outside what we can find within us. The highest solace in life, therefore, is the study of wisdom; whoever has found it is happy, and whoever possesses it is blessed.