Theory Of Definite Variation
But the question now arises, whether both Darwinism and Lamarckism must
not be replaced, or at least reduced to the level of accessory theories
and factors, by another theory of evolution which was in the field before
Darwin, and which since his time has been advanced anew, especially by
Naegeli, and has now many adherents who support it in whole or in part.
This view affects the very foundations of the Darwinian doctrine. The
theory of "indefinite" variation, bringing about easy transitions and
affecting every part of the organism separately, which is the necessary
correlate of the "struggle for existence," is rejected altogether.
Evolution takes place only along a few definite lines, predetermined
through the internal organisation and the laws of growth. It is wholly
indifferent to "utility," and brings forth only what it must according to
its own inner laws, not seldom even the monstrous. According to this view,
new species arise, not in easy transition, but with a visible leap, by a
considerable and far-reaching displacement of the organic equilibrium.
What Darwin calls the correlation of parts, and in no way denies, is here
maintained in strong opposition to his doctrine of the isolated variation
of individual parts; every member or character of the organism depends
upon others, and variation of one affects many, and in some way all of the
This theory is for the most part intended by its champions to be purely
naturalistic. But every one of its points yields support to teleological
considerations, most obviously so the concrete instances of correlation.
If any one were to attempt to make a theory of evolution from a decidedly
teleological standpoint, he would probably construct one very similar to
the one we are now considering.
It is noteworthy that it has generally been the botanists who have
especially supported these views of saltatory evolution in a definite
direction and according to internal law, who have therefore tended to
react most strongly from Darwinism. We find examples in Naegeli's large and
comprehensive work, "Mechanisch-physikalische Theorie der
Abstammungslehre"; and, before him, in Wigand's "Darwinismus und die
Naturforschung Newton's und Cuvier's"; in von Koelliker's "Heterogenesis";
in von Baer's "Endeavour after an End"; in the chapter added by the
translator, Bronn, to the first German edition of the "Origin of Species,"
where he urges weighty objections against the theory of selection, and
refers to the "innate impulse to development, persistently varying in a
definite direction"; in Askenasy's oft-quoted "Beitraege zur Kritik der
Darwinschen Lehre," also referring to "variation in a definite direction,"
for instance, in flowers; in Delpino's views, and in the works of many
other older writers. But we must leave all these out of account here,
since we are concerned only with the present state of the question.