Abscheulich!

Natural History, March, 2000 by Stephen Jay Gould

Haeckel's distortions did not help Darwin.

Revolutions cannot be kind to prominent and unreconstructed survivors of a superseded age. But the insight and dignity of vanquished warriors, after enough time has elapsed to quell the immediate passions of revolt, often inspire a reversal of fortune in the judgment of posterity. (Even the most unabashed Northerner seems to prefer Robert E. Lee to George McClellan these days.)

This essay details a poignant little drama in the lives of three great central European scientists caught in the intellectual storm of Darwin's Origin of Species, published in 1859. This tale, dormant for a century, has just achieved a vigorous second life, based largely on historical misapprehension and creationist misuse. Ironically, once we disentangle the fallacies and supply a proper context for understanding, our admiration must flow to Darwin's two most prominent opponents from a dispersed and defeated conceptual world: the Estonian (but ethnic German) embryologist and general naturalist Karl Ernst von Baer (1792-1876), who spent the last forty years of his life teaching in Russia; and the Swiss zoologist, geologist, and paleontologist Louis Agassiz (1807-1873), who decamped to America in 1846 and founded Harvard's Museum of Comparative Zoology, where I now reside as curator of the collection of fossil invertebrates that he began. By contrast, our justified criticism must fall upon the third man in the topsy-turvy drama, the would-be hero of a new world order: German naturalist Ernst Haeckel (1834-1919), the primary enthusiast and popularizer of Darwin's great innovation. Haeckel's forceful, eminently comprehensible, if not always accurate, books appeared in all major languages and surely exerted more influence than the works of any other scientist, including Darwin and Huxley (by Huxley's own frank admission), in convincing people throughout the world about the validity of evolution.

Cynic that I am, I nonetheless confess to hero worship for the raw intellectual breadth and power of three great men: Darwin, who constructed my world; Antoine-Laurent Lavoisier, because the clarity of his mind leaves me awestruck every time I read his work; and Karl Ernst von Baer, who lived too long and became too isolated to win the proper plaudits of posterity. T. H. Huxley, who ranks fourth on my list, regarded von Baer as Europe's greatest pre-Darwinian naturalist.

As the leading embryologist of the early nineteenth century, von Baer discovered the mammalian egg cell in 1827 and, in 1828, published the greatest monograph in the history of the field: Uber Entwickelungsgeschichte der Thiere (On the Developmental History of Animals). He then suffered a mental breakdown and never returned to the field of embryology. Instead he moved to Saint Petersburg in 1834 (a common pattern for Central European scientists, because Russia, lacking a system of modern education, imported many of its leading professors in scientific subjects). There he enjoyed a long and splendid second career as an Arctic explorer, a founder of Russian anthropology, and a geomorphologist credited with discovering an important law relating the erosion of riverbanks to the Earth's rotation.

Von Baer's theories of natural history allowed for limited evolution among closely related forms but not for substantial transformation between major groups. Moreover, he held no sympathy for Darwin's mechanistic views of evolutionary causality. Darwin's book shook the aged von Baer from decades of inactivity in his former zoological realm, and this great man--whom Agassiz, in his last (and posthumously published) article of 1874, would call "the aged Nestor of the science of Embryology"--came roaring back with a major critique entitled Uber Darwins Lehre (On Darwin's Theory).

In another article written in 1866 to criticize a brave new world that often forgot, and more frequently disparaged, the discoveries of previous generations, von Baer made a rueful comment that deserves enshrinement as one of the great aphorisms in the history of science. Invoking Agassiz, his younger friend and boon companion in rejecting the new theory of mechanistic evolution, von Baer wrote:

   Agassiz says that when a new doctrine is presented, it must go through
   three stages. First, people say that it isn't true, then that it is against
   religion, and in the third stage, that it has long been known. (Author's
   translation)

Ernst Haeckel, with his characteristic mixture of gusto and bluster, fancied himself a Darwinian general embattled in Agassiz's first two stages, unfurling the new evolutionary banner not only for a biological truth but for righteousness of all stripes. In 1874 he wrote:

   On one side spiritual freedom and truth, reason and culture, evolution and
   progress stand under the bright banner of science; on the other side, under
   the black flag of hierarchy, stand spiritual slavery and falsehood,
   irrationality and barbarism, superstition and retrogression.... Evolution
   is the heavy artillery in the struggle for truth.