"An unrestricted belief in causality leads necessarily to the idea that the world is an automaton of which we ourselves are only little cog-wheels. This means materialistic determinism. It resembles very much that religious determinism accepted by different creeds, where the actions of men are believed to be determined from the beginning by a ruling of God. ...The notion of divine predestination clashes with the notion of free will, in the same way as the assumption of an endless chain of natural causes. On the other hand, an unrestricted belief in chance is impossible, as it cannot be denied that there are a great many regularities in the world; hence there can be, at most, 'regulated accident'. One has to postulate laws of chance which assume the appearance of laws of nature or laws for human behaviour. ...Our philosophy is dualistic in this respect; nature is ruled by laws of cause and laws of chance in a certain mixture. How is this possible? Are there no logical contradictions? Can this mixture of ideas be cast into a consistent system in which all phenomena can be adequately described or explained? What do we mean by such an explanation if the feature of chance is involved ? What are the irreducible or metaphysical principles involved? Is there any room in this system for free will or for the interference of deity? ...The statement, frequently made, that modern physics has given up causality is entirely unfounded. Modern physics, it is true, has given up or modified many traditional ideas; but it would cease to be a science if it had given up the search for the causes of phenomena. ...I shall survey the development of physical thought, dwelling here and there on special points of interest, and I shall try to apply the results to philosophy in general."