After we had thus gained an insight into the physical characteristics of the races and social groups of man, we took up a consideration of his mental life. The mental traits common to all mankind are those which appear by contrasting man with animals; and we pointed out briefly that articulate language, the use of implements, and the power of reasoning, belong to all members of the human species as opposed to the higher animals. Before we entered into the comparison of the mental life of primitive man and of civilized man, we had to clear away a number of misconceptions caused by the current descriptions of the life of primitive man. We saw that the oft-repeated claim that he has no power to inhibit impulses, no power of attention, no originality of thought, no power of clear reasoning, could not be maintained; and that all these faculties are common to primitive man and to civilized man, although they are excited on different occasions. This led us to a brief consideration of the question whether the hereditary mental faculty was improved by civilization, an opinion that did not seem plausible to us. The study of the problem of the relation of racial descent to cultural advancement required a determination of the question in how far these are correlated. We endeavored to gain an insight into this problem by following out the relations between human types, languages, and cultures. A general lack of correlation appeared, which led us to infer that the present types of man are older than the present linguistic families, and that each type developed a number of languages. Since these must be considered the product of the mental activities of each type, uninfluenced or almost uninfluenced by other types, we tried to discover whether one language could be shown to be superior to others, and whether some languages made higher forms of thought impossible. The results of this inquiry were quite analogous to those obtained in our inquiry into the physical characteristics of man, and showed similar traits in all languages, and also that languages were moulded by thought, not thought by languages.