It has been said that sociology has succeeded in dealing with those social phenomena which extend themselves through vast periods of time, and has failed in dealing with those whose interest and {14} existence is limited to lives of a few particular generations. Now between these two sets of phenomena, as thus far described, the most obvious difference is, no doubt, the difference in their magnitude. This difference, however, is altogether accidental, and does nothing to explain those curiously contrasted results which the study of one set and the other has yielded to the modern sociologist. The difference, which will explain these, is of quite another kind, and may briefly be stated thus. The larger social phenomena—those which interest the speculative philosopher, and with which sociology has dealt successfully, are phenomena of social aggregates, or masses of men regarded as single bodies; the smaller phenomena—those which interest the practical man, and with which sociology has dealt unsuccessfully—are essentially the phenomena not of social aggregates, but of various parts of aggregates. Let us illustrate the matter provisionally by two rudimentary examples. As an example of the larger phenomena let us take the advance of man from the age of stone to the ages of bronze and iron. Of the smaller, we may take the phenomena referred to by Mr. Kidd—namely, the appearance in the modern world of the socialist or collectivist party, and the antagonism between it and the party of private property and individualism. Now the first of these two sets of phenomena—the use by men of stone implements, and the subsequent use of metal implements—consist of phenomena which, so far as the {15} sociologist is concerned, are manifested successively by humanity, or some portion of humanity, as a whole. They are not referred to individuals or small classes. No question is asked as to what particular savage may rightly claim priority in the invention of metal implements, or whether flint or bronze were the subjects of any prehistoric monopoly. Those races amongst which the use of the metals became general are regarded as a single body, which had made this advance collectively. They are, indeed, as we shall again have occasion to observe, habitually described under the common name of _Man_. But let us turn to such phenomena as the antagonism between individualists and collectivists, and the case is wholly different. It is true that here also, as in the case we have just been considering, our attention is called to a portion of the human race, namely, the Western or progressive nations, which we may, for certain purposes, regard as a single aggregate; but it is fixed, not on the phenomena which this aggregate exhibits as a whole, but on those exhibited by unlike and conflicting parts of it—the part which sympathises with individualists on the one hand, and the part which sympathises with collectivists on the other.