But if the staunchest Roman Catholic and the staunchest Presbyterian had been exchanged when infants, and if they had been brought up with home and all other influences reversed, we can have very little doubt what the result would have been. It is consistent with all our knowledge of psychology to conclude that each would have grown up holding exactly the opposite beliefs to those he holds now...and each would then have felt as sure of the truth of his opinion as he now feels—of the truth of the opposite opinion. The same thing is true, of course, of many beliefs other than those of a religious nature. If we had grown up in a community where polygamy or head-hunting, or infanticide, or gladiatorial fighting, or dueling, was regarded as the normal and natural thing—then we should have grown up to regard it as "obviously" natural and perfectly moral and proper. If an English baby had been adopted and brought up in a German home, and had grown up with no knowledge that his parents were English, all the sentiments and beliefs of that person would be "German" and not "English." Many of our beliefs—many of our most deeply rooted and fundamental convictions—are held simply as a result of the fact that we happen to have been "brought up" to them.