In discussing the emergence and development of evolutionary biology, historians of biology typically divide the nineteenth and twentieth centuries into four eras. The first, the pre-Darwinian period, came prior to publication of the Origin of Species in 1859, and it includes evolutionary theorizing by figures like Lamarck and Chambers. The second period focused on the reception and reaction to Darwin's work by the public, religious authorities, and natural scientists. This period lasted from 1859 to about 1880 and is best characterized by works that systematically examine the reception of Darwin's ideas across different countries (Glick, 1974). Beginning about 1880 and lasting through most of the 1930s is a period widely described as the "eclipse of Darwinism" or the "eclipse of Darwin."1 Biologists and historians of biology alike have described this period as one during which many theories competed for status. During these years, Darwinian evolutionary theory was supposedly obscured, and ultimately discarded, as speculative and old-fashioned natural history. Finally, beginning about 1940, a collection of geneticists, organismal biologists, and statisticians produced what Julian Huxley termed the modern "evolutionary synthesis," which brought together Darwinism and Mendelism, mutationism and modern genetics.
This paper focuses on the period of so-called eclipse. Unfortunately, much of our understanding of this eclipse comes from scientists of the synthesis era and historians who have been unduly influenced by them. For example, in Evolution: The Modern Synthesis, Huxley (1942) explained that during the 1910s evolutionary scientists were scattered, confused, and contradictory. Huxley explained how Mendelians contradicted the neo-Lamarckians, mutationists fought with Weismannians who were also fighting with the neo-Lamarckians, experimental embryologists opposed the classical recapitulatory theories of development, and the followers of newer disciplines, like genetics, considered the zoologists who clung to Darwinism to be antiquated naturalists rather than true scientists. Another architect of the modern evolutionary synthesis, Ernst Mayr, described the early twentieth century as rife with opposition to Darwinism. He pointed to the threat Darwinism posed to the argument from design, the lasting influence of essentialism, and the ambiguity of terms and phrases such as selection, species, and survival of the fittest. Historians of science, as we shall see, have perpetuated claims made by synthesis authors about the work done by the previous generation of biologists. Some who have written about the development of evolutionary theory after Darwin have gone as far as simply ignoring an entire generation of biologists. For example, Ruse's "really big book" (600+ pages), Monad to Man (1996), on the two-and-a-half-century history of evolutionary theory ignores nearly every American biologist of the early twentieth century and claims there were no American researchers "working on evolution for its own sake" during this period.2 For those historians who write about the time between T. H. Huxley and Julian Huxley, the era of the eclipse of Darwin was a time of great upheaval, and Darwinism was, at best, just one of a number of competing theories of evolution. At worst, it was considered litde more than speculation that had been discarded by most working biologists. The eclipse ended, the current literature claims, in the early 1940s with technical and disciplinary developments to evolutionary science that brought about the modern evolutionary synthesis.
I argue here that the phrase "eclipse of Darwinism" is inappropriately and problematically employed by historians of biology. The eclipse is a deterministic metaphor of darkness that establishes a discontinuous history of evolutionary theory. The era of the eclipse of Darwin was, according to the current literature, a time when the bright light of Darwin's theory of evolution by natural selection was obscured by competing mediodologies, by the speculative nature of the work done by its adherents and by an onslaught of competing tiieories of evolutionary change. …