190 THE STRUCTURE OF EVOLUTIONARY THEORY
more sharply defined. As the two sets grew along their orthogonal pathways, they
became alternate centers of nucleation for the full realm of evolutionary ideas. All
major items of this new conceptual world fell to one side or the other—as though
two suns had entered an originally homogeneous universe, and all particles had to
enter either one or the other gravitational system. Lamarck's two-factor theory
separated the universe of evolutionary concepts into a set of dichotomies best
characterized as antinomies, an unfamiliar word designating contradictions
between two equally binding principles (and originally used to specify differences
between ecclesiastical and secular law when both vied for domination in medieval
states). The precipitation of ideas about Lamarck's two axes established a long list
of antinomies that, in an important way, has set the agenda of evolutionary biology
ever since. Darwin opposed this structure of antinomies; others have advanced
strong defenses, in whole or in part. The modern theory of hierarchy depends upon
a selective defense, but in a manner radically different from Lamarck's
formulation. Consider a few key items:
IDEAL ORDER (REAL) VS. DISRUPTION (DISTURBING). The interpretation of
diversification by adaptation as lateral to, and disruptive of, an underlying lawful
regularity marks an old tradition that Darwin fought fiercely by elevating the
supposed "disturbing" force to the cause, by extrapolation, of all evolution.
Curiously, since old traditions die hard, this antinomy remains potent (even under a
Darwinian rubric) in the common claim that anagenesis, or evolutionary trends in
lineages, should be viewed as distinct from cladogenesis, or diversification—and
that speciation is, in Julian Huxley's words (1942, p. 389), "a biological luxury,
without bearing upon the major and continuing trends of the evolutionary process."
Behind this issue, of course, and particularly well expressed in this first
antinomy, stands the ancient credo of essentialism. Just as the essence or type
never becomes fully incarnate in an actual object (because any material being must
be subject to all the slings and arrows of outrageous fortune in our palpable world
of accidents), so does the outside world of changing environments deny full
expression to the ideal march of progress.
PROGRESS VS. DIVERSITY. Lamarck's expression of the fundamental VS. the
disruptive; note Huxley's words above for a modern expression.
INTERNAL VS. EXTERNAL, OR INTRINSIC VS. INTERACTIVE. The march of
progress is intrinsically and internally generated as a consequence of the chemical
properties of matter; this march represents the "essential" process of life, moving
ever forward in the absence of any push or disturbance from external forces.
Lamarck makes this contrast explicit in arguing that the march of progress would
proceed to smooth completion even in an absolutely constant environment.
IMMANENCE VS. UNPREDICTABILITY. The forces of progress, arising as
consequences of chemical laws, generate a set of predictable products inherent in
the constitution of nature. Since the chain is constantly replenished by spontaneous
generation, all stages exist at all times, and the entire sequence constitutes a
permanent part of nature. But the disturbing force of environmental