Thus far man has been treated only biologically, as individual. We must advance to man in society. Almost one half of Comte's bulky work is devoted to this side of the inquiry. Social phenomena are a class complex beyond any which have yet been investigated. So much is this the case and so difficult is the problem presented, that Comte felt constrained in some degree to change his method. We proceed from experience, from data in fact, as before. But the facts are not mere illustrations of the so called laws of individual human nature. Social facts are the results also of situations which represent the accumulated influence of past generations. In this, as against Bentham, for example, with his endless recurrence to human nature, as he called it, Comte was right. Comte thus first gave the study of history its place in sociology. In this study of history and sociology, the collective phenomena are more accessible to us and better known by us, than are the parts of which they are composed. We therefore proceed here from the general to the particular, not from the particular to the general, as in research of the kinds previously named. The state of every part of the social organisation is ultimately connected with the contemporaneous state of all the other parts. Philosophy, science, the fine arts, commerce, navigation, government, are all in close mutual dependence. When any considerable change takes place in one, we may know that a parallel change has preceded or will follow in the others. The progress of society is not the aggregate of partial changes, but the product of a single impulse acting through all the partial agencies. It can therefore be most easily traced by studying all together. These are the main principles of sociological investigation as set forth by Comte, some of them as they have been phrased by Mill.