text: You are required to cure a disease that is chronic and serious, – one which affects the general weal. You have as serious a business on hand as a physician has during a plague. Are you concerned about words? Rejoice this instant if you can cope with things. When shall you learn all that there is to learn? When shall you so plant in your mind that which you have learned, that it cannot escape? When shall you put it all into practice? For it is not sufficient merely to commit these things to memory, like other matters; they must be practically tested. He is not happy who only knows them, but he who does them. You reply: "What? Are there no degrees of happiness below your 'happy' man? Is there a sheer descent immediately below wisdom?" I think not. For though he who makes progress is still numbered with the fools, yet he is separated from them by a long interval. Among the very persons who are making progress there are also great spaces intervening. They fall into three classes, as certain philosophers believe. First come those who have not yet attained wisdom but have already gained a place near by. Yet even that which is not far away is still outside. These, if you ask me, are men who have already laid aside all passions and vices, who have learned what things are to be embraced; but their assurance is not yet tested. They have not yet put their good into practice, yet from now on they cannot slip back into the faults which they have escaped. They have already arrived at a point from which there is no slipping back, but they are not yet aware of the fact; as I remember writing in another letter, "They are ignorant of their knowledge." It has now been vouchsafed to them to enjoy their good, but not yet to be sure of it. Some define this class, of which I have been speaking, – a class of men who are making progress, – as having escaped the diseases of the mind, but not yet the passions, and as still standing upon slippery ground; because no one is beyond the dangers of evil except him who has cleared himself of it wholly. But no one has so cleared himself except the man who has adopted wisdom in its stead.