But the development of human societies has not been guided by human reason. Men have not consciously made general happiness the end of their actions. They have been conducted by passion and ambition and have never known to what goal they were moving. For if reason had presided, progress would soon have been arrested. To avoid war peoples would have remained in isolation, and the race would have lived divided for ever into a multitude of isolated groups, speaking different tongues. All these groups would have been limited in the range of their ideas, stationary in science, art, and government, and would never have risen above mediocrity. The history of China is an example of the results of restricted intercourse among peoples. Thus the unexpected conclusion emerges, that without unreason and injustice there would have been no progress. It is hardly necessary to observe that this argument is untenable. The hypothesis assumes that reason is in control among the primitive peoples, and at the same time supposes that its power would completely disappear if they attempted to engage in peaceful intercourse. But though Turgot has put his point in an unconvincing form, his purpose was to show that as a matter of fact "the tumultuous and dangerous passions" have been driving-forces which have moved the world in a desirable direction till the time should come for reason to take the helm. Thus, while Turgot might have subscribed to Voltaire's assertion that history is largely "un ramas de crimes, de folies, et de malheurs," his view of the significance of man's sufferings is different and almost approaches the facile optimism of Pope--"whatever is, is right." He regards all the race's actual experiences as the indispensable mechanism of Progress, and does not regret its mistakes and calamities. Many changes and revolutions, he observes, may seem to have had most mischievous effects; yet every change has brought some advantage, for it has been a new experience and therefore has been instructive. Man advances by committing errors. The history of science shows (as Fontenelle had pointed out) that truth is reached over the ruins of false hypotheses.