To be sure the problem of division of labor, as it appears in the subdivision of manufacture, is intimately connected with many other related questions. It quickly leads to the much larger question of division of labor in our general social structure, which is necessary for our social life with its vocational and professional demands, and which undoubtedly narrows to a certain degree every individual in the completeness of his human desires. No man in modern society can devote himself to everything for which his mind may long. But as a matter of course these large general problems of civilization lie outside of the realm of our present inquiry. In another direction the problem of monotony comes very near to the question of fatigue. But we must see clearly that these two questions are not identical and that we may discuss monotony here without arguing the problem of fatigue. The frequent repetition of the same movement or of the same mental activity certainly may condition an objective fatigue, which may interfere with the economic output, but this is not the real meaning of the problem of monotony. About fatigue we shall speak later. Here we are concerned exclusively with that particular psychological attitude which we know as subjective dislike of uniformity and lack of change in the work. Within these limits the question of monotony is, indeed, frequently misunderstood in its economic significance. Let us not forget that the outsider can hardly ever judge when work offers or does not offer inner manifoldness. If we do not know and really understand the subject, we are entirely unable to discriminate the subtler inner differences. The shepherd knows every sheep, though the passer-by has the impression that they all look alike. This inability to recognize the differences which the man at work feels distinctly shows itself even in the most complicated activities. The naturalist is inclined to fancy that the study of a philologist must be endlessly monotonous, and the philologist is convinced that it must be utterly tiresome to devote one's self a life lone to some minute questions of natural science. Only when one stands in the midst of the work is he aware of its unlimited manifoldness, and feels how every single case is somehow different from every other.