It is the first definition and use of the word in literature. If we accept it as a typical presentation of the Greco-Roman view, seen by a man of exceptional genius and insight at the climax of the period, there are two or three points which must arrest our attention. Lucretius is thinking mainly of progress in the arts, and especially of the arts as they affect man's happiness. There is no mention of increase in knowledge or in love. As in the famous parallel passage in Sophocles' _Antigone_, it is man's strength and skill which most impressed the poet, and his skill especially as exhibited in the arts. Compared with what we shall see as typical utterances of later times, it is an external view of the subject. The absence of love as an element of progress carries with it the absence of the idea of humanity. There is no conception here, nor anywhere in classical thought before the Stoics, of a world-wide Being which has contributed to the advance and should share fully in its fruits. Still less do we find any hint of the possibilities of an infinite progress. The moral, on the contrary, is that we should limit our desires, banish disturbing thoughts, and settle down to a quiet and sensible enjoyment of the good things that advancing skill has provided for us. It is, of course, true that thoughts can be found in individual writers, especially in Plato and Aristotle, which would largely modify this view. Yet it can hardly be questioned that Lucretius here represents the prevalent tone of thoughtful men of his day. They had begun to realize the fact of human progress, but envisaged it, as was natural in a first view, mainly on the external side, and, above all, had no conception of its infinite possibilities. When we turn to typical utterances of the next great age in history the contrast is striking. Catholic doctrine had absorbed much that was congenial to it from the Stoics, from Plato and Aristotle, but it added a thing that was new in the world, a passionate love and an overpowering desire for personal moral improvement. This is so clear in the greatest figures of the Middle Ages, men such as St. Bernard and St. Francis, and it is so unlike anything that we know in the world before, that we are justified in treating it as characteristic of the age. To some of us, indeed, it will appear as the most important element in the general notion of progress which we are tracing. It so appeared to Comte.[2] Of numberless passages that might be quoted from fathers and doctors of the Church, a few words from Nicholas of Cusa must suffice. He was a divine of the early fifteenth century, true to the faith, but anxious to improve the discipline of the Church. To him progress took an entirely spiritual form. 'To be able to understand more and more without end is the type of eternal wisdom.... Let a man desire to understand better what he does understand and to love more what he does love and the whole world will not satisfy him.'