|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
Rather unexpectedly, Johannes Müller and his son Max arrived in Helgoland for two-weeks of research on echinoderms (starfish, sea urchins, etc.). Müller immediately invited Haeckel and la Valette to accompany his son and him on their fishing and research expeditions. The friendship of his revered teacher and the marvel of the invertebrates they brought up for study each day irrevocably altered the course of Haeckel's research interests, from botany to marine invertebrate zoology, a transition sealed with the publication the next year of his maiden research article in Müller's Archiv.16
Haeckel extended his stay in Berlin through the winter semester of 1854-1855 but returned to Würzburg the following spring. He spent the summer term of 1855 in clinical training and in the fall would commence with the actual treatment of patients. During the summer, though, he also found time to take a small course in the dissection of invertebrates offered by the Privatdozenten Franz Leydig (1821-1905) and Carl Gegenbaur (1826-1903), both of whom worked with Kölliker. Haeckel's clinical experience was confined usually to the poor and destitute of Würzburg, and the cases with which he dealt—in children, for example, horrible worms, rickets, scrofula, and eye diseases—did little to stimulate his appetite for the practice of medicine. The only part he really enjoyed was the post-mortem anatomies, of which there seemed to be no short supply. His salvation during this period lay in the tutelage of Virchow, who encouraged the young student in pathological anatomy. Virchow oversaw Haeckel's next two publications, which embroiled him in a controversy with his mentor's opponents.17 "But how sweet to be attacked in defense of Virchow," he wrote to his parents.18 After a successful competitive anatomy exam, Haeckel became Virchow's assistant for the summer of 1856, and harbored the hope that the great man would take him along in the autumn to the University of Berlin, to which the renowned scientist had been called. But during that summer, Haeckel began again to despise the clinical practice of medicine and longed to be able to pursue what he thought his true vocation—biological research. Moreover, though his relationship with Virchow was cordial, the cool and reserved character of the professor ill complemented the passionate and volatile nature of the student.
After the tedious summer weeks of clinical work, Haeckel was invited by Kölliker to travel with him to Nice for collecting and anatomical study of invertebrates. Haeckel rejoiced at the opportunity, made good with the help of some one hundred-fifty Reich's dollars from his father. On the beautiful French Riviera, the company met Johannes Müller, and the whole experience convinced the young scientist that he had entered paradise. But the bliss of biology gave way again to dreaded medicine, and in the winter semester of 1856-1857, Haeckel retreated to Berlin to prepare his medical dissertation, which he wrote under the guidance of Leydig. His study was on the histology of river crabs (De telis quisbusdam Astaci fluviantilis),19 a subject of conveniently ambiguous disciplinary direction. He received his doctorate in March 1857, and then felt compelled to spend the summer in Vienna for further clinical study, to prepare for the state medical exam, which, after more anxious preparation in Berlin during the winter semester, he passed the following March.
During his medical education, Haeckel became ever more passionate about his vocation, not that of a physician, but that of a biological researcher, one whose ideal was formed in the exacting microscopical work done under the guidance of Kölliker and Virchow but whose deeply rooted inclinations drew him toward the kind of science practiced by Humboldt and Goethe.
Habilitation and Engagement
After passing his state medical examinations, Haeckel laid plans for the prosecution of his true vocation, research science. He arranged with Johannes Müller to conduct his habilitation study at Berlin—the habilitation, with its required monograph, being a prerequisite for an academic position. During this period, though, Müller suffered from the deepest of depressions, which led him to the ultimate solution. He took his own life with an overdose of opium—at least that was what Haeckel suspected.20 Haeckel was devastated, not simply because of a lost opportunity, but because he truly revered and loved the man.
Haeckel's academic ambitions brightened when another Müller protégé, Carl Gegenbaur, his friend from Würzburg, invited him to visit Jena, where Gegenbaur had become ordinary professor of anatomy in the medical faculty.21 During the visit in May 1858, Gegenbaur offered intimations of support, and more straightforwardly asked Haeckel if he would care to travel to Messina in October with him. To Haeckel it seemed a dream materialized, and he quickly said yes. The dream began to dissolve, however, when Gegenbaur and Moritz Seebeck (1805-1884), the curator of the University, took him aside to offer the advice of wisdom and age, that he should not even think about marriage lest his scientific career sink before being properly launched. That evening, with obviously troubled conscience, Haeckel sat down to write of this conversation to Anna Sethe, his first cousin and the woman to whom he had become secretly engaged two days after Müller’s burial.22
Haeckel had first met his cousin at the wedding of his brother Karl and Anna's sister Hermine. In his diary for 21 September 1852, when he was eighteen and she seventeen, he penned: "Celebration at Karl's wedding. Anna Sethe as an elf! Dancing. I knew how but couldn't dance and sat (as usual when others are having fun) in a melancholy mood by myself in the back of the room."23 Haeckel would see Anna from time to time at various family gatherings. In 1856 she came with Haeckel's parents to visit him in Würzburg. After the death of her father, she and her mother moved to Berlin in 1857, during the time Haeckel spent working on his dissertation. Through the next year their relationship ripened, and in precipitous passion at the time of Müller's death, he asked her to marry him. It was only two months later that Gegenbaur and Seebeck offered their peremptory advice, which was often repeated by friends and relatives to whom he reveal his secret.24
The difficulties of managing both marriage and a career—a career that had not even really begun—agitated Haeckel through the summer of 1858 and beyond. But simultaneously he came to perceive Anna as the lodestar of his life—even more, as an all-consuming love that gave meaning to his work and, it is no exaggeration, to the universe. She was in many ways the young, long-haired, blond, blue-eyed scientist's female double, either in blood or in his own imagination, as his description for a friend suggests:
A true German child of the forest, with blue eyes and blond hair and a lively natural intelligence, a clear understanding, and a budding imagination. She puts no stock in the so-called higher and finer world, for which I hold her even higher since she was brought up in it. She is rather a completely unspoiled, pure, natural person.25
Haeckel's letters to Anna over the period of their courtship express three intertwined themes: his love for her; his hopes of landing a professorship, which would allow them to marry; and his exuberant and irrepressible attachment to nature, an emotion that at times seemed to rival that for her. But through this period, the latter themes gradually become submerged in an overflow of desire for Anna. "How our souls have already so closely and strongly grown together," he exclaimed to her in August, "so that absolutely nothing can separate them and so that every thought and every action are able to be realized only with and in the 'other ego.'" He thought of her love as a kind of salvation, a life-line that would pull him back from the dark abyss of materialism toward which he felt himself dragged by his science. "When I press through from this gloomy, hopeless realm of reason to the light of hope and belief—which remains yet a puzzle to me—it will only be through your love, my best, only Anna."26
Their growing love pressed them to reveal officially what by mid-summer most of their friends knew already; and so on 14 September 1858, in Anna's new family home in Heringsdorf (north of Berlin on the Baltic Sea), they announced and celebrated their engagement. Two weeks later Haeckel wrote to his fiancée from Berlin, recalling with febrile delight their Sunday morning walk on that festive day.
My gay, frisky roe trotted by my side, happy and free over rocks and roots, slipping through thorns and thickets. [They sat down on the green-moss bank] and your sighing breath, your warm cheek on mine announced to me at every blissful second that sweet unspeakable happiness that I held in my arms, close and sure, so that I might never, never lose it. Then we lay on my good old plaid, placed on the natural bed of the forest, upholstered with dry beech leaves, sloping down on the side, at the foot of two old boughs, and we peered through the thousand smaller and larger holes carved out for us between the round, green leaves up into the deep blue cloudless sky, whose bright sun so wonderfully shown on the happy pair as if it rejoiced with them. O Anna, those were moments I will never, never forget, moments of the greatest human happiness, the most happy because the individual himself is completely forgotten; he removes himself purely and completely from the dirty, spotted veil of a suffering personality in which he is wrapped, and lifts himself up and beyond into a full and pure intuition of the other in the joy of an absolute giving to the other. One forgets heaven and heart, past and future, and lives purely and completely in the present. Here Faust himself could exclaim, >Tarry a while, you are so beautiful,= so he might secure the moment which sadly only too quickly dissolves.27
In the August prior to their engagement, Haeckel had traveled again to Jena, invited by Gegenbaur for the celebration of the three-hundredth anniversary of the University. During this visit his new mentor mentioned that he would likely not travel to Italy, and so their planned trip together would be cancelled. Haeckel decided he had to make the trip nonetheless, even if he had to go it alone. It would be an excursion not simply to secure a subject for his Habilitationschrift, but also one of Bildung, of intellectual and personal formation. He planned to spend the spring of 1859 in Florence and Rome studying art, the summer in Naples, where he would begin his marine research, and finish in Palermo and Messina in winter. As a version of the kind of trip he always dreamed of, he expected his travel would "reform and give rebirth to my whole outlook on life."28 Both Haeckel’s itinerary and his sentiment echo Goethe’s, as described in the poet’s Italienische Reise (Italian journey, 1816-1829).