It is true, as Dewey holds, that the historical method may furnish a basis for interpretation, as well as description. But the mere scrutiny of what has happened will not reveal the elements, nor determine their significance. The historian must approach his material with something more than his eyes. But there are many historical methods. Which shall be used in dealing with the development of morals?[160] Chemistry, for instance, in interpreting the fusion of hydrogen and oxygen into water, employs a system of atoms related to each other in a mathematical order, and something similarly definite must underlie the study of morals. The historical method, in general, needs no defence, but since it takes many forms, great care must be exercised in its application. Dewey seems to ignore these difficulties. Dewey's argument now leads him to a comparison of the evolutionary methods with the intuitional and empirical methods in ethics. In making the comparison, he does not propose to raise the question of fact concerning the existence of intuitions. The question to be confronted is rather a logical one, concerning the validity of beliefs. "Under what conditions alone, and in what measure or degree, are we justified in arguing from the existence of moral intuitions as mental states and acts to facts taken to correspond to them?"[161] The answer is that the existence of a belief argues nothing as to its validity. The intuitionist takes his belief as a brute fact, unrelated to objective conditions. The 'inexpugnable' character of the belief cannot establish its validity, because the life of a single individual occupies but a brief span in the continuity of the social life in which the belief is embedded. Beliefs last for generations, and then very often disappear. "What guarantee have we that our present 'intuitions' have more validity than hundreds of past ideas that have shown themselves by passing away to be empty opinion or indurated prejudice?"[162] Intuitionism has no way of guaranteeing its beliefs. The evolutionary method, on the other hand, is able to determine the validity of beliefs. "The worth of the intuition depends upon genetic considerations. In so far as we can state the intuition in terms of the conditions of its origin, development, and later career, in so far we have some criterion for passing judgment upon its pretensions to validity.... But if we cannot find such historic origin and functioning, the intuition remains a mere state of consciousness, a hallucination, an illusion, which is not made more worthy by simply multiplying the number of people who have participated in it."[163] Certain savage races, for instance, possessed moral intuitions which made the practice of infanticide an obligation. But the fact that it was universally held does not establish its validity. It must be condemned or justified by the results to which it led.