It required about a thousand years for the Greek shepherds from the pastures of the Danube to assimilate the culture of the highly civilized regions in which they first appeared as barbarian destroyers. They accepted the industrial arts of the eastern Mediterranean, adopted the Phoenician alphabet, and emulated the Phoenician merchant. By the seventh century before our era they had towns, colonies, and commerce, with much stimulating running hither and thither. We get our first traces of new intellectual enterprise in the Ionian cities, especially Miletus, and in the Italian colonies of the Greeks. Only later did Athens become the unrivaled center in a marvelous outflowering of the human intelligence. It is a delicate task to summarize what we owe to the Greeks. Leaving aside their supreme achievements in literature and art, we can consider only very briefly the general scope and nature of their thinking as it relates most closely to our theme. The chief strength of the Greeks lay in their freedom from hampering intellectual tradition. They had no venerated classics, no holy books, no dead languages to master, no authorities to check their free speculation. As Lord Bacon reminds us, they had no antiquity of knowledge and no knowledge of antiquity. A modern classicist would have been a forlorn outlander in ancient Athens, with no books in a forgotten tongue, no obsolete inflections to impose upon reluctant youth. He would have had to use the everyday speech of the sandal-maker and fuller. For a long time no technical words were invented to give aloofness and seeming precision to philosophic and scientific discussion. Aristotle was the first to use words incomprehensible to the average citizen. It was in these conditions that the possibilities of human criticism first showed themselves. The primitive notions of man, of the gods, and of the workings of natural forces began to be overhauled on an entirely new scale. Intelligence developed rapidly as exceptionally bold individuals came to have their suspicions of simple, spontaneous, and ancient ways of looking at things. Ultimately there came men who professed to doubt everything. As Abelard long after put it, "By doubting we come to question, and by seeking we may come upon the truth." But man is by nature credulous. He is victimized by first impressions, from which he can only escape with great difficulty. He resents criticism of accepted and familiar ideas as he resents any unwelcome disturbance of routine. So criticism is against nature, for it conflicts with the smooth workings of our more primitive minds, those of the child and the savage.