One fruitful cause of difficulty in the relations of science and religion is to be found in the narrowness and incapacity of well-meaning Christians who unnecessarily bring the doctrines of natural and revealed religion into conflict, by misunderstanding the one or the other, or by attaching obsolete scientific ideas to Holy Scripture, and identifying them with it in points where it is quite non-committal. Much mischief is also done by a prevalent habit of speaking of all, or nearly all, the votaries of science as if they were irreligious. A second cause is to be found in the extravagant speculations indulged in by the adherents of certain philosophical systems. Such speculations often far overpass the limits of actual scientific knowledge, and are yet paraded before the ignorant as if they were legitimate results of science, and so become irretrievably confounded with it in the popular mind. A third influence, more closely connected with science itself, arises from the rapidity of the progress of discovery and of the practical applications of scientific facts and principles. This has unsettled the minds of men, and has given them the idea that nothing is beyond their reach. There is thus a vague notion that science has overcome so many difficulties, and explained so many mysteries, that it may ultimately satisfy all the wants of man and leave no scope for religious belief. Those who know the limitations of our knowledge of material things may not share this delusion; but there is reason to fear that many, even of scientific men, are carried away by it, and it widely affects the minds of general readers. Again, science has in the course of its growth become divided into a great number of small specialties, each pursued ardently by its own votaries. This is beneficial in one respect; for much more can be gained by men digging downward, each on his own vein of valuable ore, than by all merely scraping the surface. But the specialist, as he descends fathom after fathom into his mine, however rich and rare the gems and metals he may discover, becomes more and more removed from the ordinary ways of men, and more and more regardless of the products of other veins as valuable as his own. The specialist, however profound he may become in the knowledge of his own limited subject, is on that very account less fitted to guide his fellow-men in the pursuit of general truth. When he ventures to the boundaries between his own and other domains of truth, or when he conceives the idea that his own little mine is the sole deposit of all that requires to be known, he sometimes makes grave mistakes; and these pass current for a time as the dicta of high scientific authority.