The logical function of language is the only one which has been studied by philosophers; that is, by the “ontologists” and the “metaphysicians.” But even their study has remained incomplete. Condillac and his school have solely considered the language which lends itself to logical analysis. Consequently, they only saw a single kind of combination which may be called the logic of signs. But, in reality, the logic of signs rests upon the logic of images, and this one on the logic of feelings. The so-called logicians thus conceive a narrow and false idea of our intellectual mechanism, when they concentrate all their attention “upon the most voluntary, but the least powerful of the three essential modes of which the mental combination admits.”[224] The logic of feelings is the art “of facilitating the combination of notions according to the connection between the corresponding emotions.” It is the most instinctive: it is the source of all the great inspirations of our intelligence. We can think nothing which contradicts it, or even which is not implied in it. But it has two grave defects. Its elements are not precise enough, and it is not at our disposal. It only operates under certain given conditions, and the appearance of these conditions does not rest with us. We see it at work, for instance, among animals, who occasionally provoke our admiration for the marvels suggested to them by this logic which is so closely bound up with the emotions. The logic of images, though less strong, is more free and precise than the logic of feelings. Nevertheless if we only had these two we should still be incapable of realising combinations conceived and prepared by us. This office belongs to the logic of signs. For to us almost entirely belongs the disposal of these signs, and it is this which has allowed of the development of abstract language and of the sciences. But we must not separate this last logic from the two others. The laws of our nature always cause the logical use of feelings and images to prevail over that of signs. Undoubtedly, the union between signs and thoughts may become direct, and moreover in the case of abstract notions, it could not be otherwise. Thus our inner world is artificially united to the outer world. We have an abstract and symbolical representation of it, without going through the feelings, or even, strictly speaking, through the images. But this relation has far less consistency than the one which is established by the involuntary intervention of images and of feelings. As the abstract sign has its origin in the sign appreciated by the senses, which itself proceeds from the relation of the muscular system with the nervous system; so, the relations between signs have their origin in the relations between images, and these, in their turn, proceed from the relations between feelings.