Tag Archives: Ernst Haeckel

July 28, 1840 (a Tuesday)

Edward Drinker Cope

On this date, the American paleontologist, herpetologist, and mammalogist Edward Drinker Cope was born. Cope was a scientist by self-study and personal nature — he held no degrees except honorary ones from Haverford College and, late in life, from the University of Munich. He made many important dinosaur discoveries in western North America but spent 20 years in a protracted battle with his archrival, O.C. Marsh, for professional prestige in what came to be known as the Great Bone Wars. Financially ruined in his later years, Cope had to sell his house and move in with his museum collections. He spent his final days on a cot surrounded by piles of bones.

Cope accepted the fact of evolution but thought that change in developmental (embryonic) timing, not natural selection, was the explanation for how evolution occurs. That is, a new developmental stage would be tacked onto the end of the developmental process, pushing the old end stage further back in development. Such was the view of the American school of self-proclaimed, so-called neo-Lamarckians, who invoked an internal drive for “accelerated growth” as well as Lamarckian inheritance of acquired characteristics to account for the seemingly linear pattern of biological evolution that they detected in specimens from the rich fossil beds of the American West. That is, new developmental stages would cause some body parts to become very well developed if those body parts were in heavy use. Thus, the neo-Lamarckians thought that variation and speciation were due to changes in timing of development in different organ systems due to use. In Europe, important contemporaneous neo-Lamarckians included the German biologist Ernst Haeckel and the British botanist George Henslow.

February 17, 1600 (a Thursday)

The statue of Bruno in the place where he was executed.

On this date, the Italian philosopher and Dominican friar Giordano Bruno was brought to the Campo de’ Fiori, a central Roman market square. His tongue in a gag, tied to a pole naked, Bruno was burned at the stake as a heretic.

The Fraternity of St. John the Beheaded recounted Bruno’s burning in this account which is considered authoritative by the Catholic Church:

But he insisted till the end always in his damned refractoriness and twisted brain and his mind with a thousand errors; yes, he didn’t give up his stubborness, not even when the court ushers took him away to the Campo de’ Fiori. There his clothes were taken off, he was bound to a stake and burned alive [e quivi spogliato nudo e legato a un palo fu brusciato vivo]. In all this time he was accompanied by our fraternity, who sang constant litanies, while the comforters tried till the last moment to break his stubborn resistance, till he gave up a miserable and pitiable life.

Bruno’s execution followed his lengthy imprisonment and trial that had begun on 27 January 1593 under the Roman Inquisition.

Bruno was born at Nola, near Naples, in 1548. Originally named Filippo, he took the name Giordano when he joined the Dominicans, who trained him in Aristotelian philosophy and Thomistic theology. Independent in thinking and tempestuous in personality, he fled the order in 1576 to avoid a trial on doctrinal charges and began the wandering that characterized his life.

In his book De l’Infinito, Universo e Mondi (On the Infinite Universe and Worlds), which was published in 1584, Bruno argued that the universe was infinite, that it contained an infinite number of worlds, and that these are all inhabited by intelligent beings:

Innumerable suns exist; innumerable earths revolve around these suns in a manner similar to the way the seven planets revolve around our sun. Living beings inhabit these worlds.

In Cena de le Ceneri (The Ash Wednesday Supper), also published in 1584, Bruno defended the heliocentric theory of Copernicus, but it appears that he did not understand astronomy very well, for his theory is confused on several points.

In still another book published in 1584, De la Causa, Principio et Uno (On Cause, Prime Origin, and the One), Bruno seemed to anticipate Einstein’s theory of relativity when he wrote:

There is no absolute up or down, as Aristotle taught; no absolute position in space; but the position of a body is relative to that of other bodies. Everywhere there is incessant relative change in position throughout the universe, and the observer is always at the center of things.

Closeup of the statue of Bruno in the Campo de’ Fiori.

Some say that Bruno was executed because of his Copernicanism and his belief in the infinity of inhabited worlds, but it may have been for theological errors, such as denying the divinity of Christ. In fact, no one knows for certain the exact grounds on which he was declared a heretic because the volume or volumes of his Roman trial is missing from the Vatican archives. The only remaining record is a summary of the trial, rediscovered on November 15, 1940 and published in 1942. Some abstracts of Giordano Bruno’s works, his interrogations, some of the records of an earlier Venetian trial in 1592 against him, and some other documents copied from the original Roman trial converge in the summary, which was probably used by the Assessor of the Holy Office of that period. In this document, Bruno is quoted in one of the last interrogations by the judges of the Holy Office (maybe in April 1599) before his execution. He defended his theories as scientifically founded and by no means against the Holy Scriptures:

Firstly, I say that the theories on the movement of the earth and on the immobility of the firmament or sky are by me produced on a reasoned and sure basis, which doesn’t undermine the authority of the Holy Sciptures […]. With regard to the sun, I say that it doesn’t rise or set, nor do we see it rise or set, because, if the earth rotates on his axis, what do we mean by rising and setting[…].

Interestingly, while there is no definitive documentary evidence of Bruno’s sexual orientation, his homosexuality has long been assumed, principally on the basis of his association with figures such as Marlowe, the accusations of “immoral conduct,” and his authorship of Il Candelaio (1582). The latter is a satiric comedy for the stage whose very title, “The Candleholder,” is a homosexual slang word of the time, perhaps best rendered in contemporary English as “The Fudgepacker” or “The Butt-bandit.” The play presents three characters who are often seen as three of Bruno’s alter egos, or three facets of Bruno himself: Manfurio, a pedantic scholar who speaks tortured Latin and loses his glasses; Bonifacio, the “candleholder” homosexual who finally ends up in his wife’s bed; and Bartolomeo, the scientist and alchemist who tries to transmute base metals into gold but fails. The final words of Bruno’s introduction to Il Candelaio tell the reader, above all, Godete dumque, e si possete state sana, et amate chi v’ama (Therefore take pleasure in things, stay as healthy as you can, and love all those who love you).

Moreover, there is no evidence of any interest on Bruno’s part in opposite-sex sexual relations.

Both historian John Addington Symonds and aesthete Walter Pater discuss Bruno in detail. Each refers to Bruno’s homosexuality as a known, if covert, fact hidden in sly innuendo. Symonds devotes an entire chapter of his groundbreaking Renaissance in Italy to the philosopher, while Pater comments in an 1889 essay that for a man of the spirit, Bruno possessed “a nature so opulently endowed [it] can hardly have been lacking in purely physical ardours.” Symonds adds that his own development as a man was due to his readings of Walt Whitman, Goethe, and Giordano Bruno: they “stripped my soul of social prejudices [so that]… I have been able to fraternise in comradeship with men of all classes and several races.”

Italian gay activist and literary historian Giovanni dall’Orto cites Bruno in his 1988 survey, “Sodomy as Phoenix: Being Homosexual in the Italian Renaissance.” In a discussion of “unnatural” desires, he notes that part of the philosopher’s offense against the Church was to ascribe the Copernican world outlook to nature itself: whatever comes from within a man is by definition within nature. Hence, Bruno’s scientific outlook challenges the very notion of “natural law” and “crime against nature.” Again quoting Bruno from De la Causa, Principio et Uno (1584):

All things are in the Universe, and the Universe is in all things: we in it, and it in us; in this way everything concurs in a perfect unity.

On August 7, 1603, the Church placed all his works on the Index Librorum Prohibitorum (List of Forbidden Books). Four hundred years (!) after his execution, official expression of “profound sorrow” and acknowledgement of error at Bruno’s condemnation to death was made during the papacy of John Paul II.

Following the 1870 Capture of Rome by the newly created Kingdom of Italy and the end of the Church’s temporal power over the city, the erection of a monument to Bruno on the site of his execution became feasible. In 1885, an international committee, including Victor Hugo, Herbert Spencer, Ernest Renan, Ernst Haeckel, Henrik Ibsen, and Ferdinand Gregorovius, was formed for that purpose. The monument was sharply opposed by the clerical party, but was finally erected by the Rome Municipality and inaugurated in 1889.

A memorial to Giordano Bruno.

On March 2, 2008, a 6-meter-tall statue of an upside-down figure, evocative of flames, was unveiled in Berlin’s Potsdamer Platz station as a memorial to Giordano Bruno and as a new reminder of the value and cost of free thought [Science 319(5869): 1467 (14 March 2008)]. The sculpture is by Alexander Polzin. Ernst Salcher of the Giordano Bruno Foundation, which helped fund the project, said the sculpture is designed to “irritate” the viewer into reflecting on the role of human reason in making the world a better place.

Also, the SETI League (not to be confused with the SETI Institute) has established “an award honoring the memory of Giordano Bruno, the Italian monk burned at the stake in 1600 for postulating the multiplicity of inhabited worlds.” It was first suggested by sociologist Donald Tarter at a SETI dinner held at the American Association for the Advancement of Science meetings in Atlanta on 17 February 1995 (coincidentally the 395th anniversary of Bruno’s death). The Bruno Award is presented annually to a person or persons making significant technical contributions to the art, science, or practice of amateur SETI.


February 16, 1834 (a Sunday)

Ernst Haeckel

On this date, the German biologist, naturalist, philosopher, physician, and artist Ernst Heinrich Philipp August Haeckel was born at Potsdam. He is probably one of the most contentious evolutionary biologists that ever lived. He abandoned his medical practice after reading Charles Darwin’s The Origin of Species in 1859 and returned to school, studying zoology and anatomy and eventually earning a position as professor in Jena.

Haeckel embraced the pre-Darwinian notion that life formed a series of successively higher forms, with embryos of higher forms “recapitulating” the lower ones. He thought that, over the course of time, evolution of new life forms occurred by the addition of new adult stages to the end of ancestral developmental sequences. Haeckel, who was very good at packaging and promoting his ideas, coined both a name for the process – “the Biogenetic Law” – as well as a catchy motto: “Ontogeny Recapitulates Phylogeny.”

Thus, according to Haeckel, embryonic development was actually a record of evolutionary history. He expressed it this way, as quoted in Russell (1916) [1]:

The organic individual… repeats during the rapid and short course of its individual development the most important of the form changes which its ancestors traversed during the long and slow course of their paleontological evolution…

The human zygote, for instance, was represented by the “adult” stage of the protists; the colonial protists represented the advancement of development to the blastula stage; the gill slit stage of human embryos was represented by adult fish. Haeckel even postulated an extinct organism, Gastraea, a two-layered sac corresponding to the gastrula, which he considered the ancestor of all metazoan species. [2][3][4]

PZ Meyers at Talk.Origins Archive [5] writes that the Biogenetic Law as conceived by Haeckel says:

…that development (ontogeny) repeats the evolutionary history (phylogeny) of the organism – that if we evolved from a fish that evolved into a reptile that evolved into us, our embryos physically echo that history, passing through a fish-like stage and then into a reptile-like stage.

Haeckel came under fire for this embryo comparison, for excluding the limb buds of the echidna embryo.

Haeckel came under fire for this embryo comparison, for excluding the limb buds of the echidna embryo.

Haeckel was so convinced of his biogenetic law that he was willing to bend evidence to support it. In 1874, he had claimed that members of all vertebrate classes pass through an identical evolutionarily conserved “phylotypic” stage, which presumably represents the form of their most recent common ancestor. Only later in development would specific differences appear, he said.

In fact, there is a highly conserved embryonic stage among the vertebrate classes; at the late tailbud stage, vertebrate embryos of most all classes possess somites, neural tube, optic anlagen, notochord, and pharyngeal pouches. However, Michael Richardson and his colleagues (1997) [6] discovered significant differences between groups at this stage. For example, in echidnas, limb buds are already present at the tailbud stage, whereas in other species, these are not seen until significantly later.

But in his illustrations of vertebrate embryos, Haeckel deceptively omitted limb buds at an early stage of the echidna, despite the fact that limb buds do exist then, in order to make his vertebrate embryos look more alike than they do in real life. Haeckel’s motive is clear from the text accompanying his drawings: “There is still no trace of the limbs or ‘extremities’ in this stage of development…”. [7]

Near the conclusion of the Brass-Haeckel Controversy [8] of 1908, after months of vociferous and emphatic denial, in the Berliner Volkszeitung published on 29 December 1908, Haeckel apparently admitted he had altered drawings of embryos, as quoted in Haeckel’s Frauds and Forgeries (1915) [9]:

To cut short this unsavory dispute, I begin at once with the contrite confession that a small fraction of my numerous drawings of embryos (perhaps 6 or 8 per cent.) are really, in Dr. Brass’s sense, falsified – all those, namely, for which the present material of observation is so incomplete or insufficient as to compel us, when we come to prepare a continuous chain of the evolutive stages, to fill up the gaps by hypotheses, and to reconstruct the missing-links by comparative syntheses… After this compromising confession of “forgery” I should be obliged to consider myself “condemned and annihilated,” if I had not the consolation of seeing side-by-side with me in the prisoner’s dock hundreds of fellow-culprits, among them many of the most trusted observers and most esteemed biologists. For the great majority of all the figures – morphological, anatomical, histological, and embryological – that are widely circulated and valued in the best text- and handbooks, in biological treatises and journals, would incur in the same degree the charge of “forgery.” All of them are inexact, and are more or less “doctored,” schematised, or “constructed.” Many unessential accessories are left out, in order to render conspicuous what is essential in form and organisation. [ellipsis in original]

The truth is that the development of embryos does not fit into the strict progression that Haeckel claimed, but it has also been shown that ontogeny (development of a fertilized ovum through to maturity) and phylogeny (development of a species over time) are closely related. That is, similar features in embryos of different species often reliably demonstrate that the species share a recent common ancestor. This is nicely summarized by Douglas Theobald online at Talk.Origins Archive [10]:

The ideas of Ernst Haeckel greatly influenced the early history of embryology in the 19th century. Haeckel hypothesized that “Ontogeny Recapitulates Phylogeny”, meaning that during its development an organism passes through stages resembling its adult ancestors. However, Haeckel’s ideas long have been superseded by those of Karl Ernst von Baer, his predecessor. Von Baer suggested that the embryonic stages of an individual should resemble the embryonic stages of other closely related organisms, rather than resembling its adult ancestors. Haeckel’s Biogenetic Law has been discredited since the late 1800’s, and it is not a part of modern (or even not-so-modern) evolutionary theory. Haeckel thought only the final stages of development could be altered appreciably by evolution, but we have known that to be false for nearly a century. All developmental stages can be modified during evolution… [emphasis in original]

'Tree of Life' by Haeckel (1866).

‘Tree of Life’ by Haeckel (1866).

Interestingly, in 1866 Haeckel created the first evolutionary tree to incorporate all life known at the time.

Although a strong supporter and defender of evolution (especially against attacks from religious leaders), Haeckel did not share Darwin’s enthusiasm for natural selection as the main mechanism for generating the diversity of the biological world. Instead, he favored a type of Lamarckism.

According to Jean-Baptiste Lamarck (1744-1829), change in the environment causes change in the behavior of individuals; altered behavior leads to greater or lesser use of a given structure or organ. Use would cause the structure to increase in size over many generations, whereas disuse would cause it to shrink or even disappear, because physical characteristics acquired by parents during their lifetimes are passed along to their offspring. The mechanism of Lamarckian evolution is quite different from that proposed by Darwin, although the predicted result is the same: adaptive change in lineages, ultimately driven by environmental change, over long periods of time.

PZ Meyers explains in his essay why Haeckel was completely wrong:

He argued that evolutionary history was literally the driving force behind development, and that the experiences of our ancestors were physically written into our hereditary material. This was a logical extension of his belief in Lamarckian inheritance, or the inheritance of acquired characters. If the activity of an organism can be imprinted on its genetics, then development could just be a synopsis of the activities of the parents and grandparents and ever more remote ancestors. This was an extremely attractive idea to scientists; it’s as if development were a time machine that allowed them to look back into the distant past, just by studying early stages of development.

Unfortunately, it was also completely wrong.

The discoveries that ultimately demolished the underlying premises of the biogenetic law were the principles of genetics and empirical observations of embryos. Lamarckian inheritance simply does not occur… DNA is the agent of heredity, and it is not modified by our ordinary actions – if you should get a tattoo, it is not also written into the chromosomes of your sperm or ova, and there’s no risk that your children will be born with “Mom” etched on their arm. The discovery that Haeckel had taken unforgivable shortcuts with his illustrations was a relatively minor problem for his theory, because the general thrust of his observations (that vertebrate embryos resemble each other strongly) had been independently confirmed. What really scuttled the whole theory was that its foundation was removed.

Much later, Haeckel attempted to develop a comprehensive philosophical system informed by biological and evolutionary findings. This system was to encompass ethics, theology, psychology, and politics. Some authors claim that Haeckel’s work was later appropriated by the Nazis who used it as justification for their racism and nationalism. [11] Others dispute that claim. Complicating this issue is the fact that, depending on whether you disparage or praise Haeckel, you are often assumed to be either a fundamentalist Christian, opposed to evolution, or an atheist, opposed to morality.

Haeckel’s major works are The History of Creation (1868) and The Riddle of the Universe (1899). Some of the terms he coined are still in use today, including ecology, phylum, phylogeny, and Protista.


  1. E. S. Russell. Form and Function (London: John Murray Ltd., 1916) p. 253.
  2. Ernst Haeckel. Generelle Morphologie der Organismen (Berlin: Georg Reimer, 1867).
  3. —————— Anthropogenie. Third edition. (Leipzig: W. Engelmann, 1879).
  4. S.J. Gould. Ontogeny and Phylogeny (Cambridge, MA: Harvard University Press, 1977).
  5. PZ Meyers. “Wells and Haeckel’s Embryos: A Review of Chapter 5 of Icons of Evolution.” The Talk.Origins Archive. Last modified 6 December 2006. Accessed on 14 July 2013 at http://www.talkorigins.org/faqs/wells/haeckel.html.
  6. Michael K. Richardson, James Hanken, Mayoni L. Gooneratne, Claude Pieau, Albert Raynaud, Lynne Selwood, and Glenda M. Wright. “There is no highly conserved embryonic stage in the vertebrates: implications for current theories of evolution and development.” Anat. Embryol. 196: 91-106 (1997). Accessed on 17 July 2013 at http://www.oeb.harvard.edu/faculty/hanken/documents/Richardson%20et%20al%201997%20Anat%20Embryol.pdf. [Archived here.]
  7. Michael K. Richardson and Gerhard Keuck, “A question of intent: when is a ‘schematic’ illustration a fraud?” Nature 410/6825: 144 (8 March 2001).
  8. “‘MAN-APES’ THE SUBJECT OF A WAR OF SCIENCE; Between Prof. Haeckel and Dr. Brass Rages a Controversy in Which Prehistoric Heads and Tails Are the Fruitful Themes.” The New York Times, 7 February 1909. Accessed on 16 July 2013 at http://query.nytimes.com/mem/archive-free/pdf?res=F30F11F83C5C15738DDDAE0894DA405B898CF1D3.
  9. J. Assmuth and Ernest R. Hull. Haeckel’s Frauds and Forgeries (Bombay: Examiner Press, 1915), pp. 14, 15.
  10. Douglas Theobald, Ph.D. “29+ Evidences for Macroevolution: The Scientific Case for Common Descent. Part 2: Ontogeny and Development of Organisms.” The Talk.Origins Archive. Last modified 17 May 2013. Accessed on 14 July 2013 at http://www.talkorigins.org/faqs/comdesc/.
  11. Daniel Gasman. “From Haeckel to Hitler: The Anatomy of a Controversy.” eSkeptic, 10 June 2009. Accessed on 14 July 2013 at http://www.skeptic.com/eskeptic/09-06-10/#feature. [Archived here.]