The young men who were growing up when Lucretius’ poem was published turned quickly to his faith, despite the fact that the Athenian garden had till then been unpopular. It could hardly have been the doctrine of hedonism—which Lucretius almost disregards—that enticed the youth. After all the hedonistic calculus was as exacting in its morality as was the stoic argument of obedience to nature. More probably it was the appeal to the imagination and the aesthetic vision disclosed by Lucretius that swept the younger generation of that time off its feet. There is another fruitful idea, the idea of progress, which first entered Roman consciousness through the work of Lucretius. Our modern belief in mechanistic progress, made into a fetish as it was after the acceptance of Darwinism, at times obstructs self-criticism and encourages fatalism to such an extent that its value as a stimulant may be almost completely negatived. A generation that could rush thoughtlessly into the most stupidly criminal war of all ages—and still blandly insist that it was the supreme fruit of civilization—has surely been gulled by a fallacious evolutionary _post hoc ergo_. It is a wholesome reminder to us post-Darwinists that the Athenians of Pericles’ day had in many respects attained to a creative culture which no nation has since succeeded in reaching. Yet read with a careful attention to all its implications, the evolutionary doctrine of progress is productive of envigorating optimism. Before Lucretius wrote—and the poet himself had not entirely shaken himself free from old beliefs—the Romans looked upon the golden age as past, and they were therefore too much reconciled with the fatalism inherent in the conviction that further deterioration was only to be expected.