ABSTRACT
Metaphysics may be said to have been the foundation of the sciences up to the XVIIth century, but the time then came when they were to be overthrown by the experimental method. Two currents of thought then developed. In the first an attempt was made to test the new causal theories by new facts, and it was thus that various medical doctrines had their birth. In the second all discussion of causes was rejected, and the only thing desired in physics and mathematics was the knowledge of the laws governing phenomena. Descartes denied the formal, efficient and final causes of Aristotle, and only recognized matter and movement. Bacon rejected the ancient doctrine of causes and professed only to accept laws derived from induction, but as a matter of fact made no difficulty of accepting various forms and causes from his own point of view. Gassendi, however, proclaimed that atoms were the principle of all things, and, although Descartes seems to refute this opinion, he uses it for his own theory of vortices ; this was merely the ancient doctrine of Epicurus renewed.
