Custom, convention and popular belief, no matter how many times they have been overthrown, have fairly reliable foundations. Popular ideas, to be sure, are products of mere unorganized experience. They are empirical; seldom if ever scientific. But though they are founded on experience which is _unorganized_, they are founded on so much of it that they are worthy of respect. Society could not long exist if it persisted in acting on beliefs altogether wrong, though it is safe to say that popular ideas are never more than approximately right. But unless and until you have either thoroughly thought over a question for yourself or have consulted an acknowledged and trustworthy authority, it is best tentatively to accept and act on common belief. To think and act differently, merely for the sake of being different, is unprofitable and dangerous, all questions of ethics aside. X THINKING AS AN ART I discovered, though unconsciously and insensibly, that the pleasure of observing and reasoning was a much higher one than that of skill and sport.—DARWIN’S _Autobiography_. To know is one thing; to do another. To know the science of thinking is not to possess the art of thinking. Yet I doubt not that there are readers who having finished, would deem it sufficient that they had the knowledge, and would feel they had gotten all the good or harm out of this book that there is in it. They would put it aside. They would think no more of it. The trouble with these good people (unfortunately I speak of the overwhelming majority) is that they expect information to apply itself. They expect that once they have learnt a thing they will act according to their knowledge. This is the very last thing a normal human being does. The only way we can ever get ourselves to apply knowledge is to do so by what will at first be a conscious effort. We shall have to devote much attention to it. Old established custom will have to be broken. We do not act according to knowledge; we act according to habit. Even after we have decided, for instance, that we ought to give a little independent thinking to a subject before reading about it, we shall very likely continue to read books without previous thought. Some people may imagine that the reason we do not practice what we learn is that we do not remember what we learn. They are mistaken. When learning German, I had much difficulty in knowing what prepositions required the genitive, dative or accusative cases. I finally learnt all of them alphabetically in their respective groups, and could rattle them off at a rate which would make most native Germans blush for envy. The only trouble was that when I came to an actual sentence requiring one of these prepositions I continually forgot to apply my knowledge. Some one would have to point an error out to me before it would occur to me to do so. Even then I would have to think long before the proper case occurred.