Each science tended to absorb the one next to it, on the ground of having reached the Positive stage earlier and more thoroughly. The evil then is really deeper and more extensive than is imagined by most of those who deplore it. It passes generally unnoticed except in the highest class of subjects. These doubtless are more seriously affected, inasmuch as they undergo the encroaching process from all the rest; but we find the same thing in different degrees, in every step of the scientific scale. Even the lowest step, Mathematics, is no exception, though its position would seem at first sight to exempt it. To a philosophic eye there is Materialism in the common tendency of mathematicians at the present day to absorb Geometry or Mechanics into the Calculus, as well as in the more evident encroachments of Mathematics upon Physics, of Physics upon Chemistry, of Chemistry, which is more frequent, upon Biology, or lastly in the common tendency of the best biologists to look upon Sociology as a mere corollary of their own science. In all cases it is the same fundamental error: that is, an exaggerated use of deductive reasoning; and in all it is attended with the same result; that the higher studies are in constant danger of being disorganized by the indiscriminate application of the lower. All scientific specialists at the present time are more or less materialists, according as the phenomena studied by them are more or less simple and general. Geometricians, therefore, are more liable to the error than any others; they all aim consciously or otherwise at a synthesis in which the most elementary studies, those of Number, Space, and Motion, are made to regulate all the rest. But the biologists who resist this encroachment most energetically, are often guilty of the same mistake. They not unfrequently attempt, for instance, to explain all sociological facts by the influence of climate and race, which are purely secondary; thus showing their ignorance of the fundamental laws of Sociology, which can only be discovered by a series of direct inductions from history.