Both men came from a long line of intellectual aristocracy. Both sought for their specific sciences philosophical values, the one was led from his scientific exposition of the unity of nature to his doctrine of Monism, the other from his studies of Socratian limitations to the doctrine of the Super-man. Both are fine types of irreproachable character, of purity of mind and heart, and have therefore a large host of disciples who reasoning from their character to their doctrines accept their judgment as ultimate truth. It is largely on this account that it behooves us to test their reasoning. Haeckel's chief writings which concern us here particularly are "Der Monismus als Band zwischen Religion und Wissenschaft. Glaubensbekenntniss eines Naturforschers, vorgetragen am 9. Oktober, 1892, in Altenburg beim 75 jährigen Jubiläum der Naturforschenden Gesellschaft des Osterlandes," and "Die Welträthsel," published in 1899, largely a reiteration and continuation of the former and based upon his previous scientific writings.

I.

Professor Haeckel claims at the outset, that "by reason only can we attain to a correct knowledge of the world and a solution of its great problems." Emotion and revelation have nothing whatever to do with the attainment of truth, experience and thought or speculation are the only two paths which lead to this goal. Neither pure speculation, as employed by Plato and Hegel, nor mere experience, such as Bacon and Mill, for example, made the basis for their realist systems, will suffice for the attainment of true knowledge, only by combining the activity of the two, the one elaborated by the sense organs and the inner sense centers, the other by the thought centers, the great center of association in the cortex

"Confession of Faith of a Man of Science: Monism as a Connecting Link between Religion and Science," 1892, 8th edition, 1899. "The Riddle of the Universe at the Close of the Nineteenth Century," Harper Brothers, Publishers, 1901.

of the brain will we learn to comprehend the real world. "Both channels of knowledge are mutually indispensable" and have entered in monism into mutual covenant. While dualism separates the world into the material world and an immaterial God, its creator, sustainer and ruler, monism recognizes one sole substance in the universe which is at once "God and nature," not in the sense, however, of materialism. which denies the existence of spirit nor in the sense of spiritualism which rejects the notion of matter, but in the sense in which, according to Haeckel, Spinoza defines it: "Matter, or infinitely extended substance, and spirit (or energy), or sensitive and thinking substance, are the two fundamental attributes or principal properties of the all-embracing divine essence of the world, the universal substance." His monistic philosophy consequently recognizes only one simple and comprehensive enigma (or riddle)—the "problem of substance." He contends that the seven world enigmas, recognized and discussed by Professor Emil du Bois-Raymond in his famous oration before the Berlin Academy of Sciences in 1880 and accepted by thinkers generally, are no longer enigmas, viz., (1) the nature of matter and force, (2) the origin of motion, (3) the origin of life, (4) the (apparently preordained) orderly arrangement of nature, (5) the origin of simple sensation, (6) rational thought and the origin of the cognate faculty of speech, (7) the question of the freedom of the will. The first, second and fifth which the Berlin professor considered entirely transcendental and insoluble Haeckel claims to have settled by his conception of substance; the third, fourth and sixth, considered by du Bois-Raymond capable of solution but extremely difficult, Haeckel thinks decisively answered by the modern theory of evolution, while he considers the seventh, the freedom of the will not an object for critical inquiry at all, but " a pure dogma based on an illusion and without real existence." In the light of this brilliant array of dictatorial statements, which have all the flavor of dogmatic infallibility, we modestly ask: Has Haeckel's mon

ism really solved this problem of substance, do we now actually know the nature of matter and force, the origin of motion and of simple sensation? With him it presents all the issues of life and death, of character and attainment; it is the great balm which brings consolation to the sorrowful and condemnation to iniquity. Does he convince us? In the "Conclusion" to his last work he makes this concession: "We grant at once that the innermost character of nature is just as little understood by us as it was by Anaximander and Empedocles twenty-four hundred years ago, by Spinoza and Newton two hundred years ago, and by Kant and Goethe one hundred years ago. We must even grant, that this essence of substance becomes more mysterious and enigmatic the deeper we penetrate into the knowledge of its attributes, matter and energy, and the more thoroughly we study its countless phenomenal forms and their evolution. We do not know the thing in itself' that lies behind these knowable phenomena." But while he acknowledges the impossibility of solving the problem of substance, he rejoices in the firm establishment of the law of substance, the fundamental law of the constancy of matter and force, on which rests his monism of the cosmos, which proves to him that there is no personal God, no immortal soul, no free will.

It seems to me that he dogmatizes from negative premises. He rejects certain answers in terms of which men have sought to solve the problem and leads us to infer that for man there is no answer urging the reader to give up searching for one. It is just here where the fundamental error of Professor Haeckel's whole argument lies. He assumes that the problem of the universe as a whole is a scientific problem and scornfully rejects the introduction of metaphysical methods. Science deals with facts and asks the question, what is their nature and order of their sequence, under what generalizations may the facts and their observed sequence be comprised. But the inquiry into the source and origin of the facts, the question why there is any experience at all and why the sequence of events presented therein is what it is, does not concern science

as such but is a metaphysical question. It is precisely this which constitutes the riddle of the universe. Professor Haeckel, however, uses the same monistic key to unlock in his latest book the mysteries of anthropology, psychology, cosmology and theology, but since the key does not fit all these locks the locks are lustily broken. Man's relation to the rest of the organic world, the soul's relation to the body, and the relation of all these to the cosmic substance are explained empirically or inductively and upon a brilliant array of empirical demonstrations his monism which constitutes the bond between religion and science is deductively established. The law of substance manifests itself in the cosmic world as the law of the conservation of energy and matter, in the organic world as the law of the evolution of matter, more specifically in the so-called psychic world as the law of evolution of energy, in the moral world as the law of the supreme rule of energy over matter. Psychology is the foundation of all sciences but it in turn presupposes a knowledge of the brain. Soul is a phenomenon of nature; psychology, therefore, is a part of physiology which legitimately employs observation, experiment and deductive speculation. A dualistic psychology, on the other hand, which assumes energy without matter is the product of pure imagination, because the law of substance can be applied to it just as little as to the doctrine of the freedom of the will. Soul is the sum of vital phenomena, bound like all other vital phenomena to a material substratum, a psychoplasm which in turn produces neuroplasm. There still reigns great confusion in the minds of men on this subject, but the law of substance justifies the monistic view. The introspective method must here be employed because it is the only one applicable to the realm of consciousness and occupies over against the scientific investigation of the senses and of language (the exact psychophysics) a peculiar position. Wundt, Virchow and Du Bois Raymond have turned summersaults in their later years when they declared psychology to be a purely mental science and in no causal connection what

soever with the natural sciences. There is only a difference in degree between man and the animal but no psychological barrier exists. The soul bound to matter is only an expression for the collective psychic functions of plasma. They are dependent upon certain chemico-physical properties and subject to metabolic changes. All living organisms are sensitive and answer to stimuli. This reflex arc consists in the beginning of one, two and three celled reflex organs. With the third cell, the soul or ganglion cell, a new function, unconscious presentation (Vorstellung), arises. Later on a fourth cell, the cell of sensation and will, appears. But as long as there are only reflexes, consciousness is still wanting. Conscious presentation is secondary. Presentation is the internal image of an external object transmitted through sensation. Unconscious memory is a very important function of the plastidule-in contradistinction from reproductive memory it is the most important difference between the organic and the inorganic. Animals also have reason and language. In the emotions the direct connection between brain function and other physiological functions is manifested. Attraction and repulsion are the source of the will which first appears in the three-celled reflex organ. The freedom of the will is disproved to-day.

The development of the soul is of great importance for monism. All processes of psychic origin belong to the sphere of cellular physiology. Every living being has a beginning of individual existence; with the origin of the new cell the new soul arises, and with it vanishes again; soul is, therefore, a physiological function of the organism to be traced back to chemical and physical processes, the mechanics of the plasma. Particularly important is the continuity of the psyche in the generative series. The great enigma of the nature and origin of the soul must be solved, if anywhere, within the process of historic evolution of the human soul from the animal soul. The methods of investigation are here those of anatomy and physiology. Among all Protists the psychic processes are still unconscious; sensation and