"St. Augustine says (I give a translation of the Latin original): 'With regard to the four following opinions concerning the soul--viz. (1) whether souls are handed on from parent to child by propagation; or (2) are suddenly created in individuals at birth; or (3) existing already elsewhere are divinely sent into the bodies of the new-born; or (4) slip into them of their own motion--it is undesirable for anyone to make a rash pronouncement, since up to the present time the question has never been discussed and decided by catholic writers of holy books on account of its obscurity and perplexity--or, if it has been dealt with, no such treatises have hitherto come into my hands.'" There must be many who will be glad to shake off the illusion of explanation which is no explanation, and to escape from the futile discussion of the possible behaviour of spirits and ghosts born in the dreams of primaeval savages. They will gladly accept the conclusion that the marvellous qualities and activities of living things and that inscrutable wonder, the mind of man, are outcomes of the orderly process of Nature no less than are the miracles which we call a buttercup, a rock crystal, a glacier, the noon-day sun! We can trace, by observation and inference, the orderly growth and development of these things from simpler things; we can discover continuity and common properties determining their diverse existence. But we find no explanation of them; we cannot account for the properties of matter which determine them, nor for the existence of anything--whether it be a drop of water, or human thought and consciousness. There are no special and exceptional "incomprehensibles" requiring us to assume that special "principles" or "spirits" are concerned with them whilst the rest are to be accounted for and explained in a more general way. Wherever we push our inquiries we come equally and inevitably, as did primaeval man, to that of which there is no explanation--the perpetual miracle, the miracle of the nature of things, of existence itself. The man of science bows his head in the presence of this all-pervading mystery. He is called arrogant by those who arrogate to themselves the right to "explain" things and to deal in vital spirits and metaphysical nostrums for that purpose. From time to time they fill with their proclamations the great silence which he has learnt to accept with reverence and humility. As the years roll on their hollow phrases are less frequent, and acquire the pathetic interest which belongs to all such decaying remnants of the thought and effort of the childhood of man.