Despair's Last Journey by David Christie Murray

By far the greater part of the theoretical wisdom of the world comes to us in the shape of legacies bequeathed by fools. A fool is not a person without knowledge or understanding -- that is an ignoramus. The true fool -- the only fool worthy of a wise man's contemplation -- is the man who knows and understands, and habitually refrains from acting according to knowledge and understanding. It is the record of the follies of such people which has built up the world's wisdom. From that record we have learned amongst many other things that the fool of understanding has one eternal refuge from himself which he seeks with a full knowledge of the fact that the shelter it affords is illusory, and that the path by which it leads him can only conduct him to greater dangers than those from which he is striving to escape. It is too late to go back now, quoth the fool; the business must be gone through to the end.

Thus if this brief diagnosis be of any value, the root of folly is to be found in the decay of will. Few men had reason to hold this belief more firmly than Paul Armstrong, and yet even now, when whatever was best in his own nature was more seriously engaged than it had ever been before, he went on to the consummation of a most undoubted and most cruel wrong, on the poor pretence that every stage he passed towards it made the passage of the next stage inevitable.