these attempts, Zöllner is fully right in saying: "That the scientists to-day set such an extremely high value on the inductive proof of the generatio æquivoca, is the most significant symptom of how little they have made themselves acquainted with the first principles of the theory of knowledge. For, suppose they should really succeed in observing the origin of organic germs under conditions entirely free from objection to any imaginable communication with the atmosphere, what could they answer to the assertion that the organic germs, in reference to their extension, are of the order of ether-atoms, and, with these, press through the intervals of the material molecules which form the sides of our apparatus?"
How little life is explained, at least according to the present state of our knowledge, also follows from the insufficiency of all attempts at defining it. The latest and most thorough attempt at such a definition of life, with which we are familiar, is that made by Herbert Spencer in his "First Principles", § 25, and in his "Principles of Biology," Vol. I, Part I, Chap. 4 and 5. Having made thorough investigations, he arrives at the general formula: "Life is the continuous adjustment of internal relations to external relations." To this definition we will not make the objection that it is nothing but a logical abstraction from the common quality of all processes and phenomena of life; for it certainly lies in the nature of a definition that it can be nothing else but that. Nevertheless, we will state that such a definition of life not only does not lead us any nearer to the comprehension of its processes, and especially of the richness and the organization of its forms and functions, but that it
clearly shows us how little the origin of life is explained. For this very definition necessarily and obviously leads us to the questions: Whence do those internal relations originate, whence their adjustment to external relations, and whence the continuity of this adjustment? The answer to these questions this definition still owes us.
Therefore, not only self-consciousness and freedom, not only sensation and consciousness, but also life and the organic, remain a phenomenon which—at least, according to the present state of our knowledge and reasoning—enters into the realm of the world of phenomena as something new that can not be explained from the foregoing, although it presupposes the foregoing as the condition, not the cause, of its appearance; and no matter whether we have to think of the modality of its origin as a sudden or as a gradual one.
§ 4. The Elements of the World, the Theory of Atoms, and the Mechanical View of the World.
The investigating and thinking mind, when it attempts to explain the appearances and forms of that which exists, finds itself led further and further back, until it finally arrives at the last elements of the world and of matter. Whether we take the problem of life as solved or unsolved, the living has matter and its subordination to the efficiency of all its chemical and mechanical powers in common with the lifeless; and the organic, in its first beginnings, stands extraordinarily near to, and is grown on the ground of, the inorganic,—if not according to the category of cause and effect, still according to that of condition and consequence, of basis and structure. Therefore we stand at last before the
question of the final elements of matter, which, indeed, constitutes organic as well as inorganic bodies.
The answer to this question is attempted by the theory of atoms: the doctrine which teaches that the whole material world is composed of simple particles which are no farther divisible, and from whose juxtaposition the chemical elements—and, in respect to their other forms of existence and combination, the whole world of bodies, with all their forms, states, and changes,—are composed.
This theory has not only the practical value that the physical (and especially the chemical) sciences can make and use their formulas most easily under the supposition of such simple primitive elements; but it also has the great theoretical merit that it has broken down the old barriers between matter and force, and has thus promoted considerably our method of regarding the world of material substances. Toward this result, scientists and philosophers—and, among the latter, the thinkers and investigators of both views of the world, the theistic and the pantheistic, the ideal and the materialistic,—have worked with equal merit, and have equally enjoyed its fruits, with perhaps the single exception of so pure a materialist as Ludwig Büchner, who, it seems, does not like to give up his old doctrine of force and matter as the two inseparable, equivalent, and equally eternal elements of the universe. That matter itself, even when looked upon from a purely physical standpoint, has an incorporeal principle; that the whole world of bodies, as such, has but a phenomenal character; that not force and matter are the two empirico-physical principles of the world, but that matter itself must be a product of elementary
force active in the atoms; these doctrines have now be pretty nearly common property of natural science and philosophy. Investigators who like Wilhelm Wundt, rise from natural science to philosophy, or such as take their starting-point from philosophy—whether they be theists, like Lotze, I. H. Fichte, Ulrici, or occupy the ground of a pessimistic pantheism, as does Eduard von Hartmann,—all share this view and its fruits.