Preyer would also reach a similar result with his above-mentioned theory of the identity of life and motion. For according to this theory, the living would
be as old and common as motion, and the organic but the dregs of life.
We may, therefore, say that, without regard to the fact that neither pantheism nor theism will ever harmonize with Fechner's solution of this contrast which gives to God exactly the same position in the world as the soul has in the body, natural science will certainly treat with great reserve a cosmo-metaphysical system which so fully upsets all results of exact investigations into the history of origin and development, and has no other proof for itself than the identity, or at least the similarity, of the abstract formula according to which the molecular motions of organisms and the cosmical motions are performed. Although we thus have to deny to the proof of this identity or similarity the weight which Fechner gives to it, nevertheless it has still no small merit, since it throws new and clearer light upon the old thought, always attractive and yet so difficult to present,—of a macrocosmus and a microcosmus, which has been often enough treated with so much natural mysticism.
Thus, in our inquiry into the development of things, we have successively arrived at four points, each of which urged us to make the confession that here something new came into existence, which can not be explained from the preceding conditions of its being; these four points were: the origin of self-consciousness, the origin of sensation and consciousness, the origin of life, and finally the elements of the universe. Arrived at the last problem, we see the confession of our ignorance increased to the still more comprehensive confession that we are really not able fully to explain anything in the world. We are able to perceive a uniformity of law in the states and
changes of things, and to abstract therefrom common laws of nature; we can observe single objects, and perceive their states and changes in their connection with one another and in their dependence on those laws. But we are not able to explain scientifically either the origin of these laws or the last physical causes of the qualities of things, which follow these laws.
We should reach the same result if we had not started from the objective world of the existing, as we were induced to do by our subject, but from theoretical investigations. Here also we should immediately find ourselves in a world of relations between subject and object, of a regularly arranged abundance of subjective and objective qualities, states and processes, of which the objective only come to our knowledge through the medium of the subjective, and of regularly arranged laws to which both the subjective and the objective are commonly subordinate. But why just these and no other qualities of the subject and of objects exist, why just these and no other laws reign, why just this and no other relation takes place between the perceiving subject and the perceived object, would remain unanswered as before.
Amidst a generation which is so fond of reveling in the thought of an extension of all the limits of our knowledge, and is inclined to proclaim as true that which it wishes and hopes, investigators are not wholly wanting who very decidedly express their consciousness of these limits of our knowledge, and at the same time combine it with the most logical scientific reasoning and investigation. Even when in detail they reach these limits from the most varying points of view, and draw
them in different directions, they all agree in confirming the principle that it is one of the first and most indispensable conditions of successful investigation always to be conscious of the limits of its perception. Voices which remind mankind of these limits, are perhaps less popular, for man prefers to be reminded of the advances rather than of the limitations of his knowledge; but they are on that account the more worthy of our gratitude, for they keep us on the solid ground of the attainable from which alone sure progress in knowledge is possible. Among such philosophers we name Ulrici, and especially Lotze; among scientists, in the first place, two pioneers in their departments—namely, in the department of the mechanism of heat, Robert von Mayer—compare his "Bemerkungen über das mechanische Aequivalent der Wärme" ("Remarks on the Mechanical Equivalent of Heat"), and "Ueber nothwendige Consequenzen und Inconsequenzen der Wärmemechanik" ("Necessary Consequences and Inconsequences of the Mechanism of Heat"), Stuttgart, Cotta;—and in the realm of the development of organisms, K. E. von Baer—compare his "Reden und kleinere Aufsätze" ("Addresses and Essays"), 2 vols., St. Petersburg, 1864 and 1876. In this connection we have already mentioned the name of DuBois-Reymond. Otto Köstlin published two remarkable dissertations in this direction—"Ueber die Grenzen der Naturwissenschaft" ("Limits of Natural Science"), Tübingen, Fues, 2d ed., 1874, and "Ueber natürliche Entwicklung" ("Natural Development"), ib., 1875. In the latter he especially cautions against hastily confounding the laws of development of planets, development of the organic kingdom, and development
of the individual organisms. Recently, Wigand, in the second volume of his work already frequently mentioned, attempts, with an extreme energy which does too little justice to the representation and investigation of the still unsolved problems, to formulate the limits of the knowable.
A contrary extreme, and of its kind a still more one-sided corrective of this too great stability, we have in those investigators who, by reason of the great progress which has been made in the realm of the theoretical knowledge of nature, allow themselves to be drawn on to the hope of still explaining all states and processes in the world—the spiritual and the ethic processes as well as the physical—from the pure mechanism of atoms; and who see in that which thus far has been mechanically explained, the only and the infallible way of explaining all that is still obscure. They call this view the mechanical view of the world; and, as "monism," put it in opposition to the "vitalistic, teleological, and dualistic view of the world." In order to obtain a correct view of this standpoint, we quote from Häckel's "Natural History of Creation", Vol. I, page 23, the following passage: "By the theory of descent we are for the first time enabled to conceive of the unity of nature in such a manner that a mechanico-causal explanation of even the most intricate organic phenomena, for example, the origin and structure of the organs of sense, is no more difficult (in a general way) than is the mechanical explanation of any physical process; as, for example, earthquakes, the courses of the wind, or the currents of the ocean. We thus arrive at the extremely important conviction that all natural bodies which are known to us are equally