568 THE STRUCTURE OF EVOLUTIONARY THEORY
feature of Darwin's thought and this leads us to consider the merit of this reaction."
Osborn then invoked a time-honored diplomatic tactic by defining Darwin's
achievement as threefold: establishment of the "law of evolution" itself,
documentation of the fact of evolution, and development of the theory of natural
selection. Since the first two propositions cannot be gainsaid, why fuss over the
third, even if Darwin overemphasized the role of natural selection? Osborn notes
(1909, p. 332): "There is some lack of perspective, some egotism, much
onesidedness in modern criticism. The very announcement, 'Darwin deposed,'
attracts such attention as would the notice 'Mt. Blanc removed.'"
Osborn correctly identifies two claims at the core of Darwinian theory: (1)
selection operates on undirected variability to cause evolutionary change (legs one
and two of my tripod); and (2) gradualism rules in geological time (leg three and
the methodological pole): "In the operations of this intimate circle of minute
variations within organisms, he was inclined to believe two things: first that the fit
or adaptive always arises out of the accidental, or that out of large and minute
variations without direction selection brings direction and fitness; second, as a
consistent pupil of Lyell, he was inclined to believe that the chief changes in
evolution are slow and continuous" (Osborn, 1909).
But Osborn then gently chides Darwin for putting too much faith in the power
of selection: "There can be no question, however, that Darwin did love his
selection theory, and sometimes overestimated its importance" (1909, p. 336).
Then, as a consummate politician and administrator, Osborn put a positive spin on
his criticism—granting ultimate praise with only a faint damn. He emphasized the
most common of all anti-Darwinian arguments— that selection can only operate as
a negative force ("judicial" rather than "creative"). But he then converted Darwin's
weakness to centennial strength with a remarkable diplomatic move: Darwin's
problems arose from his ignorance of heredity, but he set a great task for us
thereby, and we must persevere:
Selection is not a creative principle, it is a judicial principle. It is one of
Darwin's many triumphs that he positively demonstrated that this judicial
principle is one of the great factors of evolution. Then he clearly set our
task before us in pointing out that the unknown lies in the laws of variation
and a stupendous task it is. At the same time he left us a legacy in his
inductive and experimental methods by which we may blaze our trail.
Therefore, in this anniversary year, we do not see any decline in the force
of Darwinism but rather a renewed stimulus to progressive search.This diplomatic theme—that Darwin did not discover an adequate mechanism
of evolution, but we celebrate his centennial because he opened up a new world of
research—became a virtual litany for symposiasts. For example, William Morton
Wheeler virtually threw selection in the ashcan as he praised Darwin: "And even if
we go so far as to say that natural selection may eventually prove to be an
unimportant factor in evolution, to be consigned to