If This be Heresy: Haeckel=s Conversion to Darwinism
Robert J. Richards
The University of Chicago
Just before Ernst Haeckel’s death in 1919, historians began piling on the faggots for a splendid auto-da-fé. Though more people prior to the Great War learned of Darwin’s theory through his efforts than through any other source, including Darwin himself, Haeckel has been accused of not preaching orthodox Darwinian doctrine. In 1916, E. S. Russell, judged Haeckel's principal theoretical work, Generelle Morphologie der Organismen, as "representative not so much of Darwinian as of pre-Darwinian thought."[1] Both Stephen Jay Gould and Peter Bowler endorse this evaluation, and see as an index of Haeckel’s heterodox deviation his use of the biogenetic law that ontogeny recapitulates phylogeny.[2] Michael Ruse, without much analysis, simply proclaims that “Haeckel and friends were not true Darwinians.”[3] These historians locate the problem in Haeckel’s inclinations toward Naturphilosophie and in his adoption of the kind of Romantic attitudes characterizing the earlier biology of Goethe. These charges of heresy assume, of course, that Darwin’s own theory harbors no taint of Romanticism and that it consequently remains innocent of the doctrine of recapitulation. I think both assumptions quite mistaken, and have so argued.[4] But against the charge of heresy, one can bring a more direct and authoritative voice, Darwin himself.
In 1863, Haeckel made bold to send Darwin his recently published two-volume monograph on radiolarians—one-celled aquatic animals that secret a skeleton of silica. The first volume examined in minute detail the biology of these creatures and argued that Darwin’s theory made their relationships comprehensible. The second volume contained extraordinary copper-plate etchings depicting the quite unusual geometry of these animals. Darwin immediately replied to this previously unknown zoologist that the volumes "were the most magnificent works which I have ever seen, & I am proud to possess a copy from the author."[5] Emboldened by his own initiative in contacting the famous naturalist, Haeckel, a few days later, sent Darwin a newspaper clipping that described a meeting of the Society of German Naturalists and Physicians at Stettin, which occurred during the previous autumn. The article gave an extended and laudatory account of Haeckel's lecture defending Darwin's theory.[6] Darwin quickly responded in his second letter: "I am delighted that so distinguished a naturalist should confirm & expound my views; and I can clearly see that you are one of the few who clearly understands Natural Selection."[7] Darwin thus judged Haeckel a true disciple, “one of the few who clearly understands Natural Selection” and one whose research ability and aesthetic sense lent considerable weight to the new evolutionary theory. Darwin thus stands as a witness against later scholars who wish to cast Haeckel from the camp of the orthodox.
Of course, contemporary historians might argue that Darwin did not understand the full scope of Haeckel’s own biological ideas and that if his German were better he would have detected deviant tendencies in the work of his new disciple. In this essay, I wish to provide further evidence that Darwin was not mistaken in his original evaluation. The full argument for this position must be postponed, but a good start can, I believe, be made by following in measured step the road Haeckel took to Damascus.
Early Student Years
Ernst Heinrich Haeckel was born 16 February 1834 in Potsdam, where his father Karl (1781-1871), a jurist, served as Privy Counselor to the Prussian Court. His mother Charlotte (née Sethe,1767-1855) nurtured him on classic German poetry, especially that of her favorite Friedrich Schiller, while his father discussed with him the nature-philosophy of Johann Wolfgang von Goethe and the religious views of Friedrich Schleiermacher, who had been an intimate of the family, especially of Haeckel's aunt Bertha. Karl Haeckel had a keen interest in geology and foreign vistas, which undoubtedly led his son to treasure the travel literature of Alexander von Humboldt and Charles Darwin, which the boy devoured, and later to yearn for a life of adventure in exotic lands. Haeckel=s judicial heritage may also have fostered a lingering impulse to bring legal clarity, through the promulgation of numerous laws, into what he perceived as ill ordered biological disciplines.
Medical School at Würzburg
Though Haeckel had harbored the desire to study botany at university, he acceded to his father’s wishes and, in August 1852, enrolled in the medical school at Würzburg. The university at that time had probably the best medical faculty in Germany. Students—some six hundred in 1852—came from all over to study with such luminaries as Albert von Kölliker (1817-1906) and Rudolf Virchow (1821-1902). Kölliker taught histology and introduced Haeckel to what would quickly flower into a sweet delight—at least for one so disposed—namely, microscopic study; and Kölliker's just-published Handbuch der Gewebelehre (1852) became his vade mecum. But the star of the faculty was Virchow, whose history of political engagement excited a frisson of danger in the active imaginations of his students. His ideas concerning the cellular basis of life and disease proved just as radical as his politics had been; and his reputation for deep research and academic controversy ensured his lectures would be jammed. His electrifying talent as a scientist indeed drew Haeckel to his classes, but his insulated and cool personality kept the two from becoming close—quite in contrast to Haeckel's relationship with Kölliker, with whom he would strongly disagree intellectually but would remain on warm personal terms throughout their years. Virchow and Haeckel would later interact in proper professional ways, until, that is, the famous senior scientist began preaching the dangers of evolutionary theory for untutored minds. In 1877, Virchow recommended to his colleagues that they not press for evolutionary theory to be taught in the German middle and lower schools, since, as he argued, it lacked scientific evidence, was an affront to religion, and smoothed the way to socialism. Haeckel's sulfuric reaction to this admonition undoubtedly released a force building since his student days.[8]
Haeckel did not take naturally to the idea of medical school and its likely consequence, clinical practice. Two lines, though, seemed to have kept him tethered to medicine: a tempered passion for the kind of fundamental science he experienced with Kölliker and Virchow; and a strategy for utilizing medicine to achieve the scientific vocation he envisioned from his reading of Humboldt. Under the affable tutelage of Kölliker, he grew to love precise work in histology, especially since he had a talent with the microscope. He could simultaneously peer with one eye through the lens and with the other draw in exquisite detail the minute structures of tissues. "Vivant cellulae! Vivat Microscopia!" he exulted to his father at Christmas in 1853. But it was Virchow's lectures during his second year that confirmed him in a resolve, made to his father, to stick with medicine. He provided his father a description of the arresting experience:
Virchow's lecture is rather difficult, but extraordinarily beautiful. I have never before seen such a pregnant concision, a compressed power, a tight consistency, a sharp logic, and yet the most insightful descriptions and compelling liveliness as are here united in lectures. Though, if one does not bring to the lectures an intense concentration and a good philosophical and general culture, it is very difficult to follow him and to get a hold of the thread that he so beautifully draws through everything; a clear understanding will be taxed considerably by a mass of dark, quickly moving expressions, learned allusions, and a large use of foreign terms, which are often very superfluous.[9]
Kölliker and Virchow, by the force of their personalities, made deep impressions on the fledgling researcher. They taught him the value of bold hypothesis and precise empirical research. But two other German scientists—by reason of their philosophical and aesthetic views—had a much more profound impact on Haeckel’s conception of nature and his future adoption of evolutionary theory. These were Alexander von Humboldt (1769-1859) and Johann Wolfgang von Goethe (1749-1832).
The Aesthetic Science of Humboldt and Goethe
In his Voyage aux Régions Equinoxiales du Nouveau Continent, fait en 1799-1804 (Travel to the equinoctial regions of the new continent, made from 1799-1804, published 1807-1834), in his Anschichten der Natur (Views of nature, 1849), and especially in his famous Kosmos (Cosmos, 1845-1862), Humboldt attempted to formulate and plait together a great many empirical laws—those characterizing astronomy, chemistry, physics, geology, botany, and zoology. He believed that the principles of those several disciplines touching on the phenomena of life all harmoniously articulated with one another, and thus demonstrated that "a common, lawful, and eternal bond runs through all of living nature."[10] The task of the natural scientist, then, was to reveal this harmony of laws producing a unified whole, to work through the vast and wondrous diversity of nature to discover the underlying forms. The harmony of nature, a cosmos, according to Humboldt, was discovered to both reason and poetic imagination. He himself proposed many quantitative principles of plant morphology and biogeography. But he was equally insistent about the necessity of cultivating the aesthetic aspects of nature, since aesthetic judgment was no less important for human understanding than mechanistic determination. "Descriptions of nature," Humboldt observed in a Kantian vein,
can be sharply delimited and scientifically exact, without being evacuated of the vivifying breath of imagination. The poetic character must derive from the intuited connection between the sensuous and the intellectual, from the feeling of the vastness, and of the mutual limitation and unity of living nature.[11]
This same basic premise, that scientific judgments and aesthetic judgments about living nature have the same structure and aim—that they deliver to comprehension the unity and diversity of nature, but portend the sublime—this premise was of Kantian origin but likely of more immediate Goethean derivation. It had been a subject of some conversation between Goethe and Humboldt during the many years of their friendship.
Goethe anchored the principle of complementarity of scientific and aesthetic judgment in his metaphysical monism, a conception Haeckel himself would adopt. Goethe, following Spinoza, conceived of nature as harboring adequate ideas, archetypes that the naturalist had to recover in order to articulate nature in scientific law and theory, and that the artist had to comprehend in order to render natural beauty in painting and poetry.[12] Haeckel's consumption of great quantities of Humboldt and Goethe during his medical school years caused his own ideas to pulse with their conceptions of science and art.
The Research Ideal
Goethean and Humboldtean ideas fueled Haeckel's own natural propensities. During his medical school days, he was hardly a solitary figure. He had good friends among his classmates, with whom he learned to lift a pint, at least on occasion; he also had several acquaintances among the faculty. [13] But in those moments of adolescent's deep reflections and inevitable anxieties, he found great consolation in the Romantics’ traditional resources—nature and poetry. After dinner, with a friend or alone, he would often steal out into the countryside to savor the delights of nature settling into evening. Or in the twilight of his darkening room, he would light a candle and pull down his Schiller, Goethe, or perhaps read from a translation of Shakespeare—a favorite of the Romantics.
Though he often felt he had two souls dwelling in one breast—that of the "loving man," who feels deeply and kindles his passions with nature and poetry, and that of the "scientific man," who splashes cold reason on the emotions to achieve objective understanding—he yet conceived of a way to temper these disjoint inclinations. This was through the Humboldtian vision of the researcher who works in exotic lands and occasionally attends to the medical needs of the natives. He used this image to fortify his efforts at medicine, which he ever hated. It was an adolescent dream, but one which, remarkably, would materialize in a few years.
Perhaps no experience confirmed Haeckel in his goal of biological (as opposed to medical) research more than his new relation with the most famous physiologist and zoologist of his day, Johannes Müller. In spring of 1854, Haeckel decided to take his summer term in Berlin. Away from provincial Würzburg, he would indulge himself in this "metropolis of intellect," and, of course, visit with his parents and relatives. He would also have opportunity to study with the renowned Müller.[14]
During the summer term at Berlin, Haeckel attended Müller’s lectures on comparative anatomy and physiology. The decisive experience with Müller, though came during the summer vacation. At the end of August, 1854, Haeckel and his friend Adolph de la Valette St. George decided to travel to Helgoland (two islands in the North Sea, west of Schleswig-Holstein). They planed to meet other student friends there for sea-weed collecting and rather desultory anatomical study—all to be refreshed by a good deal of sea bathing. Most likely Müller's stories of collecting off the islands, along with other tourist delights, inspired them to go. On the way they passed through the port city of Hamburg, whose shops carried exotic wares from all over the globe and whose streets could hardly contain the crowds of sailors, tourists, peddlers, and citizens of all stations and dress. The harbor itself displayed to the entranced students a tangled forest of masts and rigging from ships that plied the seas of the world. After a harrowing passage on a new three-masted iron steamer during a great gale, Haeckel and la Valette disembarked on the principal island of Helgoland in the late afternoon of 17 August. They settled into a routine of sea-bathing at 6:00 a.m. and collecting and dissecting during the rest of the day. It was a revealing experience for Haeckel, as he indicated to his parents: "You cannot believe what new things I see and learn here every day; it exceeds by far my most exaggerated expectations and hopes. Everything that I studied for years in books, I see here suddenly with my own eyes, as if I were cast under a spell, and each hour, which brings me surprises and instruction, prepares wonderful memories for the future."[15]