As to the philosophy of evolution, we know that, with regard to the origin of the principles of thought, it consists in linking the experience of present generations to that of generations past; in substituting secular for individual experience--in a word, in filling up by the accumulation of ages on ages the interval existing between particular and contingent facts and the universality of principles. This hypothesis is always at bottom no other than that of the _tabula rasa_, only it is no longer the individual who is this _tabula rasa_, since each one has, by heredity, received a pre-formed intelligence. Nevertheless, under pain of contradicting the hypothesis, we are forced to admit that there was a first subject who, prior to the action of the object, must have been this _tabula rasa_. But here the objections of Leibnitz reappear. What can a pure, abstract, and unmodified subject be? And again, before any meeting of subject with object, we have to admit a pure object having nothing subjective, just as the subject had nothing objective. What shall we affirm of this pure object? Let us divest it if you will of colour, heat, sound; must we not at least conceive it as extended, as existing in time, conceive it, that is, according to the necessary forms that are supposed to be suppressed? For to say that it has been capable of existing without having anything in common with these forms, and that out of this unknown and nameless condition have arisen, by way of transformation, the notions of which we treat, were to admit that something _can_ come out of nothing. We must therefore acknowledge that universal notions do at least exist as germs at the origin of evolution. It is not evolution that has created them, evolution has only developed them, and be they ever so attenuated, they still remain conditions without which nothing can be thought. Such is the gist of the first part of M. Liard's book, and we have nothing to add to it but our approbation. We can but admire the skilful analysis with which it begins, and the vigorous discussion accompanying that analysis. The three stages traversed by the experimental philosophy of our days--namely, Positivism, the Associative Philosophy, and that of Evolution--are competently and precisely summed up. The discussion is cogent, solid, and could not be further developed without injury to the unity of the work. No doubt it requires close attention to follow it; but it is lucid and well sustained. Whatever the difficulty metaphysic may encounter in constituting itself a science, and getting recognized as such, it has been established that empiricism is not a tenable position, since it has been found necessary to pass from positivism to association, from association to evolution; while evolution itself still supposed some pre-formation. One thing is certain, intelligence invariably contains a something that does not come from without--namely, intelligence itself. II.