Judgment.

Thinking is man’s only basic virtue, from which all the others proceed. And his basic vice, the source of all his evils, is that nameless act which all of you practice, but struggle never to admit: the act of blanking out, the willful suspension of one’s consciousness, the refusal to think - not blindness, but the refusal to see; not ignorance, but the refusal to know. It is the act of unfocusing your mind and inducing an inner fog to escape the responsibility of judgment - on the unstated premise that a thing will not exist if only you refuse to identify it, that A will not be A so long as you do not pronounce the verdict "It is.”

Independence is the recognition of the fact that yours is the responsibility of judgment and nothing can help you escape it—that no substitute can do your thinking—that the vilest form of self-abasement and self-destruction is the subordination of your mind to the mind of another, the acceptance of an authority over your brain, the acceptance of his assertions as facts, his say-so as truth, his edicts as middle-man between your consciousness and your existence.

Ayn Rand, from Atlas Shrugged