The Riddle of the Universe at the close of the nineteenth century

by Ernst Haeckel

The fantastic notions which the Christian Church disseminates as to the eternal life of the immortal soul after the dissolution of the body are just as materialistic as the dogma of “the resurrection of the body.” In his interesting work on Religion in the Light of the Darwinian Theory, Savage justly remarks: “It is one of the standing charges of the Church against science that it is materialistic. I must say, in passing, that the whole ecclesiastical doctrine of a future life has always been, and still is, materialism of the purest type. It teaches that the material body shall rise, and dwell in a material heaven.” To prove this one has only to read impartially some of the sermons and ornate discourses in which the glory of the future life is extolled as the highest good of the Christian, and belief in it is laid down to be the foundation of morality. According to them, all the joys of the most advanced modern civilization await the pious believer in Paradise, while the “All-loving Father” reserves his eternal fires for the godless materialist.

In opposition to the materialist athanatism, which is dominant in the Christian and Mohammedan Churches, we have, apparently, a purer and higher form of faith in the metaphysical athanatism, as taught by most of our dualist and spiritualist philosophers. Plato must be considered its chief creator: in the fourth century before Christ he taught that complete dualism of body and soul which afterwards became one of the most important, theoretically, and one of the most influential, practically, of the Christian articles of faith. The body is mortal, material, physical; the soul is immortal, immaterial, metaphysical. They are only temporarily associated, for the course of the individual life. As Plato postulated an eternal life before as well as after this temporary association, he must be classed as an adherent of “metempsychosis,” or transmigration of souls; the soul existed as such, or as an “eternal idea,” before it entered into a human body. When it quits one body it seeks such other as is most suited to its character for its habitation. The souls of bloody tyrants pass into the bodies of wolves and vultures, those of virtuous toilers migrate into the bodies of bees and ants, and so forth. The childish naïvety of this Platonic morality is obvious; on closer examination his views are found to be absolutely incompatible with the scientific truth which we owe to modern anatomy, physiology, histology, and ontogeny; we mention them only because, in spite of their absurdity, they have had a profound influence on thought and culture. On the one hand, the mysticism of the Neo-Platonists, which penetrated into Christianity, attaches itself to the psychology of Plato; on the other hand, it became subsequently one of the chief supports of spiritualistic and idealistic philosophy. The Platonic “idea” gave way in time to the notion of psychic “substance”; this is just as incomprehensible and metaphysical, though it often assumed a physical appearance.

The conception of the soul as a “substance” is far from clear in many psychologists; sometimes it is regarded as an “immaterial” entity of a peculiar character in an abstract and idealistic sense, sometimes in a concrete and realistic sense, and sometimes as a confused tertium quid between the two. If we adhere to the monistic idea of substance, which we develop in [chap. xii]., and which takes it to be the simplest element of our whole world-system, we find energy and matter inseparably associated in it. We must, therefore, distinguish in the “substance of the soul” the characteristic psychic energy which is all we perceive (sensation, presentation, volition, etc.), and the psychic matter, which is the inseparable basis of its activity—that is, the living protoplasm. Thus, in the higher animals the “matter” of the soul is a part of the nervous system; in the lower nerveless animals and plants it is a part of their multicellular protoplasmic body; and in the unicellular protists it is a part of their protoplasmic cell-body. In this way we are brought once more to the psychic organs, and to an appreciation of the fact that these material organs are indispensable for the action of the soul; but the soul itself is actual—it is the sum-total of their physiological functions.

However, the idea of a specific “soul-substance” found in the dualistic philosophers who admit such a thing is very different from this. They conceive the immortal soul to be material, yet invisible, and essentially different from the visible body which it inhabits.

Thus invisibility comes to be regarded as a most important attribute of the soul. Some, in fact, compare the soul with ether, and regard it, like ether, as an extremely subtle, light, and highly elastic material, an imponderable agency, that fills the intervals between the ponderable particles of the living organism, others compare the soul with the wind, and so give it a gaseous nature; and it is this simile which first found favor with primitive peoples, and led in time to the familiar dualistic conception. When a man died, the body remained as a lifeless corpse, but the immortal soul “flew out of it with the last breath.”

The comparison of the human soul with physical ether as a qualitatively similar idea has assumed a more concrete shape in recent times through the great progress of optics and electricity (especially in the last decade); for these sciences have taught us a good deal about the energy of ether, and enabled us to formulate certain conclusions as to the material character of this all-pervading agency. As I intend to describe these important discoveries later on (in [chap. xii].), I shall do no more at present than briefly point out that they render the notion of an “etheric soul” absolutely untenable. Such an etheric soul—that is a psychic substance—which is similar to physical ether, and which, like ether, passes between the ponderable elements of the living protoplasm or the molecules of the brain, cannot possibly account for the individual life of the soul. Neither the mystic notions of that kind which were warmly discussed about the middle of the century, nor the attempts of modern “Neovitalists” to put their mystical “vital force” on a line with physical ether, call for refutation any longer.

Much more widespread, and still much respected, is the view which ascribes a gaseous nature to the substance of the soul. The comparison of human breath with the wind is a very old one; they were originally considered to be identical, and were both given the same name. The anemos and psyche of the Greeks, and the anima and spiritus of the Romans, were originally all names for “a breath of wind”; they were transferred from this to the breath of man. After a time this “living breath” was identified with the “vital force,” and finally it came to be regarded as the soul itself, or, in a narrower sense, as its highest manifestation, the “spirit.” From that the imagination went on to derive the mystic notion of individual “spirits”; these, also, are still usually conceived as “aëriform beings”—though they are credited with the physiological functions of an organism, and they have been photographed in certain well-known spiritist circles.

Experimental physics has succeeded, during the last decade of the century, in reducing all gaseous bodies to a liquid—most of them, also, to a solid—condition. Nothing more is needed than special apparatus, which exerts a violent pressure on the gases at a very low temperature. By this process not only the atmospheric elements, oxygen, hydrogen, and nitrogen, but even compound gases (such as carbonic-acid gas) and gaseous aggregates (like the atmosphere) have been changed from gaseous to liquid form. In this way the “invisible” substances have become “visible” to all, and in a certain sense “tangible.” With this transformation the mystic nimbus which formerly veiled the character of the gas in popular estimation—as an invisible body that wrought visible effects—has entirely disappeared. If, then, the substance of the soul were really gaseous, it should be possible to liquefy it by the application of a high pressure at a low temperature. We could then catch the soul as it is “breathed out” at the moment of death, condense it, and exhibit it in a bottle as “immortal fluid” (Fluidum animae immortale). By a further lowering of temperature and increase of pressure it might be possible to solidify it—to produce “soul-snow.” The experiment has not yet succeeded.

If athanatism were true, if, indeed, the human soul were to live for all eternity, we should have to grant the same privilege to the souls of the higher animals, at least to those of the nearest related mammals (apes, dogs, etc.). For man is not distinguished from them by a special kind of soul, or by any peculiar and exclusive psychic function, but only by a higher degree of psychic activity, a superior stage of development. In particular, consciousness—the function of the association of ideas, thought, and reason—has reached a higher level in many men (by no means in all) than in most of the animals. Yet this difference is far from being so great as is popularly supposed; and it is much slighter in every respect than the corresponding difference between the higher and the lower animal souls, or even the difference between the highest and the lowest stages of the human soul itself. If we ascribe “personal immortality” to man, we are bound to grant it also to the higher animals.

It is, therefore, quite natural that we should find this belief in the immortality of the animal soul among many ancient and modern peoples; we even meet it sometimes to-day in many thoughtful men who postulate an “immortal life” for themselves, and have, at the same time, a thorough empirical knowledge of the psychic life of the animals. I once knew an old head-forester, who, being left a widower and without children at an early age, had lived alone for more than thirty years in a noble forest of East Prussia. His only companions were one or two servants, with whom he exchanged merely a few necessary words, and a great pack of different kinds of dogs, with which he lived in perfect psychic communion. Through many years of training this keen observer and friend of nature had penetrated deep into the individual souls of his dogs, and he was as convinced of their personal immortality as he was of his own. Some of his most intelligent dogs were, in his impartial and objective estimation, at a higher stage of psychic development than his old, stupid maid and the rough, wrinkled manservant. Any unprejudiced observer, who will study the conscious and intelligent psychic activity of a fine dog for a year, and follow attentively the physiological processes of its thought, judgment, and reason, will have to admit that it has just as valid a claim to immortality as man himself.