Although sociology is defined as the science of society, in reality it cannot deal with human groups, which are the immediate concern of its research, without in the end tackling the individual, the ultimate element of which these groups are composed. For society cannot constitute itself unless it penetrates individual consciousnesses and fashions them 'in its image and likeness'; so, without wanting to be over-dogmatic, it can be said with confidence that a number of our mental states, including some of the most essential, have a social origin. Here it is the whole that, to a large extent, constitutes the part; hence it is impossible to try to explain the whole without explaining the part, if only as an after-effect. The product par excellence of collective activity is the set of intellectual and moral goods called civilization; this is why Auguste Comte made sociology the science of civilization. But, in another aspect, it is civilization that has made man into what he is; it is this that distinguishes him from the animal. Man is man only because he is civilized. To look for the causes and conditions on which civilization depends is therefore to look, as well, for the causes and conditions of what, in man, is most specifically human. This is how sociology, while drawing on psychology, which it cannot do without, brings to this, in a just return, a contribution that equals and exceeds in importance the services it receives from it. It is only through historical analysis that it is possible to understand what man is formed of; for it is only in the course of history that he has taken form.