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The Eclipse of Darwinism around 1900

The period around 1900 saw intense debates on the mechanisms of evolution, with scrutiny on Darwin's theory of natural selection. Scientists expressed doubts on randomness in evolution, leading to anti-Darwinism movements. Figures like Samuel Butler, Edward Drinker Cope, August Weismann, and Herbert Spencer played key roles. The rise of Neo-Lamarckism and the Baldwin Effect added complexities to evolutionary theory, highlighting the interplay between learned behavior and genetic encoding.

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The Eclipse of Darwinism around 1900

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  1. The Eclipse of Darwinism around 1900 Much of the debate that followed publication of the Origin focused on the question of evolution itself, rather than on Darwin’s proposed mechanism. After the fact of evolution had become established, however, Darwin’s proposed mechanism came under close scrutiny. Beginning about 1880, many scientists—including some of Darwin’s most ardent defenders—expressed discomfort with the element of randomness in the theory of natural selection, suspecting that random variation, even if selected, could not alone produce the seemingly endless examples of living biological adaption. This situation led to the advocacy of various strands of anti-Darwinism, ultimately culminating in a crisis for Darwinism around 1900, a period Julian Huxley would later refer to as the “eclipse of Darwinism”.

  2. Samuel Butler, victorian novelist (1835-1902)

  3. The American school of Neo-Lamarckian Paleontology Bitter feud with O. C. Marsh over both his Neo-Lamarkianism and dinosaur fossils Religious motivation in his denial of Darwinism Edward Drinker Cope, American Paleontologist (1840-1897) at Haverford College from 1864-1870?

  4. Darwinism purged of its “Lamarckian” elements! (but in fact unleashed a backlash of anti-Darwinian sentiment) August Weismann (1834-1814) In 1889 cut the tails off of 1,500 rats over 20 generations

  5. Das Keim Plasma: a theory of heredity (1892) From Simpson, GG, Life: An introduction to Biology, 1957 (modified from Wilson, EB, The Cell in Development and Evolution, 1896)

  6. Feud between Herbert Spencer and Weismann Herbert Spencer, “The inadequacy of natural selection”, 1893 Weismann, “The Allmacht (all-sufficiency) of natural selection”, 1893 “Unpermissibly weak!” “As if that were certain!”

  7. Neo-Lamarckism continues deep into 20th Century The Inheritance of Acquired Characteristics, 1924 (English Translation) Paul Kammerer (1820-1926)

  8. Conrad Hal Waddington (1905–1975) Epigenetic Landscape Organisers and Genes, 1940 Branching Track Model of Development

  9. Genetic Assimilation (Waddington, 1953) (idea also developed by I. I. Schmalhausen, referred to as “stabilizing selection”)

  10. “Organic” Evolution "A New Factor in Evolution” (1896) by American psychologist James Mark Baldwin American Naturalist 30: 441-451,536-553. (also Lloyd Morgan and Henry Fairfield Osborn at about same time) Coined the “Baldwin Effect” by G. G. Simpson in an article whose purpose was to challenge importance of the idea “The Baldwin Effect” (1953) Evolution 7: 110-117 The learned (voluntary or conscious?) behavior of a species or group can shape the evolution of that species or group. Learned Behavior Genetically Encoded Instinct

  11. Hinton and Nowlan’s Simulation of the Baldwin Effect [Put Figure on here] Hinton and Nowlan (1987) How learning can guide evolution Complex Systems 1: 495-502.

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