This is the primary cause of rock climbing accidents. "Judgement," in this sense includes self-control,common sense, and mental alertness, as well as the exercise of prudence, and of clearly seeing the reality of a climbing situation, and the reality of one's capacity to respond to it.

... Safety in rock climbing lies almost entirely within this "judgement" area. Little is left to chance. Equipment is a minor factor. With the best equipment in the world, the man with poor judgement is in mortal danger, whereas he who has sound judgement is safe with nothing but tennis shoes because he will not venture beyond the limits of his equipment and capabilities.

If we are keenly alert and aware of the rock and what we are doing on it, if we are honest with ourselves about our capabilities and weaknesses, if we avoid committing ourselves beyond what we know is safe, then we will climb safely. For climbing is an exercise in reality. He who sees it clearly is on safe ground, regardless of his experience or skill. But he who sees reality as he would like it to be, may have his illusions rudely stripped from his eyes when the ground comes up fast.

We are, of course, all mixtures of sanity and folly, of clear vision and murky romanticism. Such conflicts are the mark of the human condition. And we climb because we are human. The rock is a field of battle between our weakness and our strength. We wouldn't touch rock if we were perfectly self-controlled. And he who would climb and live must continuously wage this battle and never let folly win. It's an outrageously demanding proposition. But I never said it was easy.