216 THE STRUCTURE OF EVOLUTIONARY THEORY
Weismann offered the same pugnacious defense for germinal selection that he
had long championed for the Allmacht of organismal selection; the argument must
hold, lest we be driven either to mysticism or to the patently false Lamarckian
mechanism:
No one who is unwilling to accept germinal selection can be compelled to
do so, as he might be to accept the Pythagorean propositions. It is not built
up from beneath upon axioms, but is an attempt at an explanation of a fact
established by observation—the disappearance of disused parts. But when
once the inheritance of functional modifications has been demonstrated to
be a fallacy ... he who rejects germinal selection must renounce all attempt
at explanation. It is the same as in the case of personal selection. No one
can demonstrate mathematically that any variation possesses selection
value, but whoever rejects personal selection gives up hope of explaining
adaptations, for these cannot be referred to purely internal forces of
development (1903, volume 2, p. 121).Weismann, at least for public consumption, insisted that germinal selection
represented the advancing wave of triumphant Neo-Darwinism. (In the late 19th
century, "Neo-Darwinism," a term coined by Romanes, referred to the
panselectionist school of Wallace and Weismann, not to the pluralism of Darwin
himself. The modern meaning, associated with the evolutionary synthesis of the
1930's and onward, is not genealogically linked to this earlier definition.) Many
critics responded by charging that this invisible process represented little more than
an ad hoc hypothesis invented to save selection from the otherwise unexplainable
phenomenon of degeneration. Kellogg (1907) provided, I believe, the most
balanced perspective. He labelled germinal selection as "a new and radically un-
Darwinian theory" (1907, p. 134)—recognizing that Darwin's own theory of
"natural selection" specified organisms as the locus of selection. But he respected
the theory, recognized its similarity with the selectionist logic of classical
Darwinism, and regarded germinal selection as a credible attempt to explain, in
expanded Darwinian terms, the apparently un-Darwinian property of directional
variation. He wrote: "Obviously Weismann in his theory of germinal selection has
preserved the actuality of the struggle and the selection, but with a 'rehabilitation'
of natural selection in the real Darwinian meaning and only fair application of the
phrase, the new theory has nothing to do. It is, much more, a distinct admission of
the inadequacy of natural selection to do what has long been claimed for it. It is the
first serious attempt at a causomechanical explanation of a theory of orthogenesis,
that is, variation along determined lines" (Kellogg, 1907, p. 199).
I particularly value Kellogg's interpretation because the logic of his argument
correctly represents, in my view, the relationship of modern hierarchical selection
theory to classical Darwinism and to the Modern Synthesis as well. Hierarchy
should be viewed as an expansion of Darwinism in its continuing reliance on
selection as the primary mechanism of evolutionary change. But,