Now, this emotional prompting toward completeness of life requires, of course, that conduct should be guided, as far as possible, in accordance with a true theory of the relations of man to the world in which he lives. Hence, at any given era the religious feeling will always be found enlisted in behalf of some theory of the universe. At any time, whatever may be their shortcomings in practice, religious men will aim at doing right according to their conceptions of the order of the world. If men's conceptions of the order of nature remained constant, no apparent conflict between their religious feelings and their knowledge need ever arise. But with the first advance in our knowledge of nature the case is altered. New and strange theories are naturally regarded with fear and dislike by persons who have always been accustomed to find the sanction and justification of their emotional prompting toward righteousness in old familiar theories which the new ones are seeking to supplant. Such persons oppose the new doctrine because their engrained mental habits compel them to believe that its establishment will in some way lower men's standard of life, and make them less careful of their spiritual welfare. This is the case, at all events, when theologians oppose scientific conclusions on religious grounds, and not simply from mental dulness or rigidity. And, in so far as it is religious feeling which thus prompts resistance to scientific innovation, it may be said, with some appearance of truth, that there is a conflict between religion and science.