Our professor is equally conclusive in his estimate of Comte’s classification of the sciences. He quite demolishes the objections made to it by Mr. Herbert Spencer in his essay with that title. M. Lévy-Bruhl repeats the criticisms to which Spencer has been exposed in this country and abroad by Littré, Lewes, Mill, and others. And he has no difficulty in showing that Mr. Spencer’s objections are due to his very slight acquaintance with Comte’s text, and his own superficial study of the English abridgments. In proposing a classification of the _concrete_ sciences, Mr. Spencer enters on a task which Comte distinctly repudiates, and which on good grounds he treats as philosophically impracticable for purposes of evolutionary sequence. Comte’s strictly _relative_ theory excludes such a scale of _concrete_ science; whilst Spencer’s _absolute_ theory of the universe forces him to attempt it in vain. If it be objected that Comte’s ascending scale of the sciences is “anthropocentric,” the answer is that, when reasonably understood as a philosophic device for sorting human ideas, not as a statement of _absolute_ truth, the “anthropocentric” arrangement of human knowledge is the only one which is at once possible and useful. It would need a long essay even to sketch M. Lévy-Bruhl’s analysis of Comte’s conception of _science_, of _law_, and of the six dominant sciences. He has thoroughly assimilated the positive spirit, that _science_ implies a co-ordination of _laws_, not an encyclopædia of facts, that it is _relative_ to our powers of observation and reasoning and not an _absolute_ explanation of the universe in itself. He goes through the sciences, physical, social, and moral, in turn, as treated by Comte, and justly explains that Comte never attempted or conceived a _vade-mecum_ or handbook of contemporary scientific knowledge, but a scheme for the co-ordination of general ideas of science. A real “philosophy of the sciences” is something wholly distinct from a compendium of all the sciences--a thing which in 1840 was far less possible than it might be now. Controversialists have reproached Comte with the obvious fact that his concrete science is now sixty years old. In dealing with these shallow criticisms, M. Lévy-Bruhl has shown how little able is any narrow specialist to understand the abstract conceptions of a real philosopher.