With regard to matter and motion, he would note that a piece might be removed and deposited by the side of the board, but was never destroyed, and he would infer that matter is indestructible and could never have been created. As for motion, the condition, the only invariable and necessary condition, of movement is previous movement, Black must move before White can: the only condition of change in the distribution of the pieces on the board would be some previous change. If the suggestion were made to him that possibly the real condition of all movement and every change was the purpose of an unseen agent, and that real knowledge was impossible without some idea of that purpose, he might as a man of science decline to accept the suggestion. The object of science is not to conjecture why things happen, or with what purpose, but to describe positively the way in which they actually do happen, or perhaps merely to describe the motions of material things in space. It does not matter with what purpose a shot or a mine is fired, or even whether with any or none: the results are just the same, if it is fired in just the same way. Science neither assumes nor denies the existence of purpose, because neither the assumption nor its rejection would in the least help her to discover the things that she wants to know. But are the things she wants to know the only things worth knowing? Every man is entitled to answer that question for himself. Are they the only things that can be known? They are the only things that can be known--on her assumptions. Just as the world can only be explained scientifically on the assumptions of science, so it can only be interpreted morally or religiously on the assumptions made by religion and morality. The only end that could be subserved by assuming a Divine purpose would be at most to enable us in some slight degree to argue what the purpose of some things might be--and that is of no interest or value to science. She declines to look for a final cause: her business is with efficient and mechanical causes.