the process rather than in the result, as a growing, expanding, changing vision, blooming with youth as long as human life can use it, it can hardly be said that his eyes have felt the touch of the spirit of modern science.
Wherever modern science has affected characteristic changes in the trend of philosophic thought, the result has been achieved by lessening the influence of that ancient legacy which may be conveniently referred to as the doctrine of final causes.
It must not be inferred, however, that the influence of this doctrine has been confined to philosophy alone. It has been felt in every field of human inquiry that presents a speculative aspect, an opportunity to reach by means of the imagination into the unknown. The history of science is one long record of struggle between just those types of mind that Poincaré has sketched. In none of the sciences, however, has the conflict been more prolonged and bitter than in biology. There the fight has been waged about the four great problems of evolution, individual development, vitalism and adaptation. None more than these offer speculative opportunity—abundantly accepted. None more convincingly than these show the inexorable incompatibility of faith in final causes and scientific progress.
I present them, therefore, as my chief aids in developing, if I may, a fruitful conception of the nature of scientific truth. Having reached such a conception, we will proceed to discuss its relation to the philosophic thought of the day.
Faith in final causes is not a necessary product of a particular civilization, of civilization at all. Though it may persist in the midst of sophistication, it is born of inexperience. Under one form or another, it has existed among peoples of all sorts, wherever they have possessed sufficient intelligence to hazard an interpretation of their universe of experience. Of these peoples, the Greeks and Hebrews claim our especial attention, since it is from them that the main streams of our philosophy and science and religion flow.
Compared with the sophistication of Aristotle's theories of life, the cosmology of the Mosaic record is strikingly anthropomorphic and naive. In spite of this naivete, however, there is no question of its astounding control over the history of scientific thought; the more so, since it is to the second and far cruder story of the creation, in fact, in the second chapter of Genesis that the church chiefly pinned its faith in its long struggle with the doctrine of evolution. The struggle has been at times debased with bitterness and violence. One grows heartsick at the sad spectacle of a Galileo swearing away his scientific probity as he groveled in fear of torture before the Inquisition.