There is some ability and considerable knowledge displayed in the volume of lectures before us, though not much originality. The author professes to take the side of Christianity against the false and mischievous theories of such men as Sir William Hamilton, of Edinburgh, J. Stuart Mill, Huxley, Darwin, Herbert Spencer, and others, whom he classes as belonging to the Positivist school. We have every disposition in the world to think and speak well of the volume, and to give it full credit for every merit it may claim. It is directed against our enemy even more than against his. Positivism is the most open, frank, honest, and respectable antagonist Christianity or Catholicity has had in modern times, and, we may add, the ablest and the most logical, especially as represented by avowed Positivists. In fighting against us, positivism fights against our Presbyterian doctor, so far as he retains any element of Catholic truth, and there is no good reason why his war against it should not tend as far as it goes to the same end as ours. Positivism can be opposed and 2 Christianity defended only on Catholic ground; and so far as Dr. McCosh really does either, he must assume our ground and serve in our ranks, or at any rate be on our side; and it would be churlish in us to reject or underrate his services because in certain other matters he is against us, or is not enrolled in our ranks. It is certain that in these lectures, which show marks of much hard mental labor, the author has said many good things, and used some good arguments; but having truth only in a mutilated form, and only his private judgment to oppose to the private judgment of Positivists, he has been unable to give a full and conclusive refutation of positivism. As a Protestant trained in Protestant schools, he has no clear, well-defined catholic principles to which he can refer the particular truths he advances, and the special arguments he urges for their unity and support. His book lacks unity, lacks the mental grasp that comprehends in its unity and universality the whole subject, under all its various aspects, or in its principle, on which it depends, and which explains and justifies it. His book is a book of particulars, of details, of general conclusions drawn from particular facts and statements, like all Protestant books. This is not so much the fault of the author perhaps as of his Protestantism, which, since it rejects catholicity and has nothing universal, is essentially illogical, and can deal only in particulars or with individual things. The contents of the book are referred to no general principle, and the particular conclusions drawn are of little value, because isolated, each standing by itself instead of being reduced to its principle and co-ordinated under its law. The author lacks the conception of unity and universality; he has particulars, but no universals--variety, but no identity--multiplicity, but no unity, except in words. This is a