When we proceed from fact to motive, we find even greater possibilities of misunderstanding. To the solicitor the one all-powerful motive for the purchase of a life insurance policy may lie in the fact that it is an excellent investment. Unless, therefore, he understands psychology and his client well enough to do otherwise, he may talk the investment feature and appeal to the investment motive when dealing with a man who cares nothing about the investment, but might respond readily and instantly if his desire to provide for the future of his wife and children were appealed to. Success in persuading, therefore, depends upon two things: First, knowledge in general as to how the human mind works; how it receives its knowledge; how it proceeds from facts and motives to conclusions; what its ambitions, desires, and other feelings are; how these may be aroused and, finally, how they may provide the motive power and induce favorable action. Second, knowledge as to how each individual human mind works; what it's particular methods are in the obtaining of information, in reasoning upon that information, and forming its conclusions; what its motives are and how these motives finally induce decision and action. The study of the first of these problems is a study of psychology. Because knowledge in regard to it can be easily obtained in practically all of the standard works of salesmanship, perhaps it is not necessary for us to go into it more deeply here. Those who wish to pursue it further, may find an exceedingly valuable discussion of it in "Influencing Men in Business," by Walter Dill Scott; "The Art of Selling," by Arthur Frederick Sheldon, and "The Science of Business Building," by Arthur Frederick Sheldon. MANY DOMINATING MOTIVES As we have already seen, one man gets his information very quickly, another must get it slowly. One demands details, another cannot endure them. But these are not the only differences. One man learns best through his eyes, another through his ears, and still another by his sense of touch. One man gets his facts most easily by reading about them, another must see the actual production, while the third forms the most definite and easily understandable mental picture of them as a result of hearing them described. One man, in buying machinery, wants to examine carefully every detail of its construction, another man wants only to see it in action and examine its product, while still another man demands both.