[158] Similarly knowledge, the opposite of ignorance, may be called the eyes and the ears of the soul. For it fixes the attention on what is said and contemplates what is, and allows no mis-seeing or mis-hearing, but surveys and observes all that is worthy to be heard and seen. And if it be necessary to travel or take ship, it makes its way to the ends of the earth or ocean, to see something more or hear something new.
[159] For nothing is so active as the passion for knowledge; it hates sleep and loves wakefulness. So it ever arouses and excites and sharpens the intellect, and compelling it to range in every direction makes it greedy to hear, and instils an incessant thirst for learning.
[160] Knowledge, then, provides that sight or hearing, to which we owe each case of right conduct. For he who sees and hears in the moral sense, knows what is good for him, and by choosing this and rejecting its opposite, finds himself benefited. But ignorance entails a more severe disablement to the soul than the disablement of the body, and thus is the cause of all its wrongdoing, since it cannot draw help from outside itself through the warnings which seeing and hearing might give it. Thus, standing utterly alone, and left unguarded and unprotected, it is a butt for the haphazard hostility of men and circumstances alike.
[161] Let us, then, never drink so deep of strong liquor as to reduce our senses to inactivity, nor become so estranged from knowledge as to spread the vast and profound darkness of ignorance over our soul.