And as Mark Twain has remarked, “When even the brightest mind in our world has been trained from childhood in a superstition of any kind, it will never be possible for that mind, in its maturity, to examine sincerely, dispassionately, and conscientiously any evidence or any circumstance which shall seem to cast a doubt upon the validity of that superstition.” Of course Mark Twain was wrong. Of course we are The Reasoning Race, as he cynically intimates we are not. To religion, for instance, the most important question which can engage our understanding, each of us always gives independent thought. It is a mere accident, of course, that almost all of the 400,000,000 Chinamen are Buddhists. It is a mere accident that the overwhelming mass of East Indians are Brahmans. It is only by chance that practically all Turks, Persians and Arabians are Mohammedans. And it merely happened to happen that England is Protestant and Ireland is Catholic. . . . But it is unsafe to bring this question of religion too near home. We now come to our third cause of desire: (3) We desire an opinion to be wrong because we would be forced to change other opinions if it were not; or we desire an opinion to be right because then we would be able to retain our other opinions. This is a most widespread form of prejudice. But I believe it is, fortunately, the most defensible. Its defensibility, however, depends mainly on the opinions we fear to change. These we may divide into two kinds: (a) Those which have been formed without thought; borrowed opinions, etc. The greatest opposition to the theory of evolution came from those conservative Christians who saw that it undermined any literal interpretation of Genesis. If these Christians had investigated the sources of that book, had considered its probable authority, had given thought to the possibility of inspired writing, and had finally decided in favor of the Biblical narrative; then—right or not—their opposition to Darwin’s theory would have been free at least from this sort of prejudice. But most of this opposition had come from persons who had not thought of Genesis, but had accepted it from the first, because it had been dogmatically hammered into their heads since childhood. Hence it was prejudice, pure and simple. (b) The second kind of opinions we fear to change are those resting mainly upon evidence. William James gives an example: