Seeds of Hierarchy 221
Following the early 20th century vogue for eugenics, Weismann used this
argument to promote a positive program of breeding to save the human race.
Germinal selection must be responsible for any decline of the human stock
engendered by relaxation of natural selection—for panmixia lacks sufficient
strength to produce such an effect, while Lamarckian inheritance does not exist.
This orthogenetic deterioration by germinal selection can only be reversed by a
reimposition of Darwinian competition in the organismal mode, with reproductive
success to the victors. Arguing that military service might operate as a good filter
for identifying bodies well suited for success in organismal selection, Weismann
suggested (1903, vol. 2, p. 147): "It would indeed be well if only those who had
gone through a term of military service were allowed to beget children" (thus
adding another example to the compendium of social nonsense advanced by
prominent evolutionists in the name of Darwinism— see Chapter 7, and Fisher,
1930).
But, far more important than merely extending the domain of germinal
selection to explain potentially nonadaptive organismal traits, Weismann also
enlarged the conceptual realm of levels in selection from a narrow mechanism for
synergism to a full theory of hierarchy. Weismann had now worked his way
through the logic of multi-level selection theory, and had recognized the two key
ingredients of any full account.
INDEPENDENCE OF LEVELS AND POTENTIAL FOR CONFLICT. The attribution of
orthogenesis to germinal selection implies that suborganismal selection can act
separately from conventional Darwinian selection, and even work in a contrary
direction to decrease phenotypic adaptation. Thus, the process that Weismann had
originally promoted to make natural selection even more effective had become, by
honest probing into all corners and implications of the argument, a separate cause
that could work either with or against the canonical Darwinian mode. In fact,
Weismann now argued that potential independence from the Darwinian level of
organismal selection establishes the primary significance for germinal selection in
evolutionary theory (1903, vol. 2, p. 119): "In this fact lies the great importance of
this play of forces within the germ-plasm, that it gives rise to variations quite
independently of the relations of the organism to the external world. In many cases,
of course, personal selection intervenes, but even then it cannot directly effect [sic,
and correctly; he means 'cause,' not just 'affect'] the rising or falling of the
individual determinants—these are processes quite outside of its influence."
In his most revealing change, Weismann even reinterprets his type case of
degeneration. He had previously tried to explain degeneration as a result of
germinal selection completing a process that natural selection had started but could
not finish. Now, without any change in evolutionary mechanics, he speaks of
germinal selection working differently and independently. He even claims that
degeneration offers the purest case for potential independence of levels—for
germinal and organismal selection usually act together, thus rendering their
individual contributions operationally inseparable. But we know that organismal
selection has disappeared in the final stages of degeneration, and we can therefore
observe the unsullied action of germinal selection alone!