208 THE STRUCTURE OF EVOLUTIONARY THEORY
by J. Arthur and Margaret R. Thomson as The Evolution Theory in 1903. A
comparison of the original 1896 version with the fullest exposition of 1902
provides a fascinating exercise in itself, and also becomes a crucial argument for
this book—for Weismann moved from a limited hypothesis proposed only as an
adjunct to natural selection to a fully articulated theory of hierarchy, including
concepts of independence and conflict between levels.
SOME ANTECEDENTS TO HIERARCHY IN GERMAN
EVOLUTIONARY THOUGHT
Germinal selection certainly finds its immediate source in Weismann's war with
Lamarckism, his debate with Spencer, and his severe, longstanding difficulty with
the problem of degeneration. But Weismann's eventual embrace of hierarchy as an
ultimate argument against Lamarckism also grew from a deeper foundation in
German evolutionary thought. This lineage of argument is virtually unknown to
English-speaking evolutionists, for the roots lie in the two most important
untranslated documents of 19th century German evolutionary biology—the
Generelle Morphologie (1866) of Ernst Haeckel and the Jugendwerk of a man who
eventually made his considerable mark in another area of biology, Wilhelm Roux's
(1881) Der Kampf der Theile im Organismus (The Battle of Parts in the
Organism). Neither Haeckel nor Roux proposed a theory of causal hierarchy across
levels of selection; both, in fact, spoke in the name of reductionism. Yet by
denying, in very different ways, the exclusivity, or even the privileged status, of
the organism as a causal agent in evolution, and by focusing attention on a
structural hierarchy of levels, both Haeckel and Roux provided central ingredients
to Weismann's theory of evolutionary hierarchy.
Haeckel's descriptive hierarchy in levels of organization
Generelle Morphologie der Organismen (1866), Haeckel's first book, represents an
eclectic mixture of militant reductionism and old-fashioned idealistic morphology;
all united to an evolutionary theory every bit as idiosyncratic. (Haeckel dedicated
volume two, jointly, to Darwin, Lamarck, and Goethe—and its central argument
represents an odd fusion of their disparate ideas.) Haeckel's later notoriety rested
almost entirely on the second volume, with its celebrated evolutionary trees (so
often reproduced in modern textbooks), based largely on his "biogenetic law,"
ontogeny recapitulates phylogeny (Gould, 1977b). The first volume, entitled
"Allgemeine Anatomie" and dedicated to Carl Gegenbaur, has largely been
forgotten. This first volume consists of two major parts, each attempting to
establish a formal science for morphological study and each, following Haeckel's
invariable practice, studded with a baroque terminology of his own construction.
(Haeckel, with a sure sense of what R. K. Merton (1965) would later call the
eponymous strategy for renown, coined new terms shamelessly, recognizing (I
suspect) that a few would probably hang on to bear his legacy (an r-selection
approach to