Or the mother who believes that her son will turn out a respectable man, does she do it because of her experiences? Her experiences are perhaps opposed to her belief; she believes, nevertheless. Circumstances were unfavorable to her son, his father does not understand his real nature, he merely enjoys his youth: thus she comforts herself. Experience is not the foundation of her belief, but her belief interprets her experience. The belief is founded on the fact that she needs it. The idea of a wayward son would deprive her of the most valued part of her existence. Therefore she cannot believe it. Misfortune of any kind has a marvelous belief-creating power, because it constantly revives ideas of remedying the misfortune. “Whoever has lived among people,” says Spinoza, “knows how full of wisdom they feel, insulted if any one should offer any advice, as long as their affairs are prosperous. But let misfortune overpower them, and they are willing to ask any one’s advice, and to accept it, however senseless and ill-considered it may be.” Experiential, authoritative, and practical belief differ according to their sources, but they appear in life in various combinations. However, one of three kinds can usually be found to be the chief component in a system of conviction. That we cannot escape the authoritative belief is plain. Who could repeat every observation made by others in order to avoid the possibility of accepting erroneous reports? Practical belief has different limits according to the amount of experience possessed by each individual. And a whole class of people having about the same kind and amount of experience may thus be distinguished from another class by their practical beliefs. A practical belief of one, which is not shared by another, is called by the latter a superstition. How much superstitions differ and how much they change is well known. Recall, for example, a superstitious means of improving one’s looks, of curing diseases, of regaining a lost love. But wherever a superstition is difficult to contradict because it is so stated as to concern only that which is beyond experience (spiritualism), or when it is supported by a famous name, it may successfully resist all attempts at overthrowing it.