Pattern and Progress on the Geological Stage 469
as a thoroughly sufficient theory of evolution unless this mechanism could also
explain evidences of pattern and vector in life's history. But how could Darwin
meet such a requirement if natural selection—as a central attribute of its radical
character and not a peripheral aspect easily withdrawn or compromised—had been
devised as a biological analog for Lyell's uniformity of state, or non-
directionalism?
I have just epitomized Darwin's dilemma in its most abstract form. In the
immediate practice of his century, one prominent example consumed nearly all
discussion of the general subject of vector and pattern—the concept of progress. If
Darwin could validate progress by natural selection, then he would solve his
dilemma of how to extract directional pattern from an apparently ahistorical
theory.
This context of validating a concept of progress in macroevolution establishes
an unconventional locus for a discussion—now to follow—on the key Darwinian
subject of "struggle" and the nature of competition in general, but I am convinced
that this topic finds its best fit at this point within the basic logic of Darwinian
argument, and that a failure to recognize this appropriate place has led many
evolutionists to underappreciate the theoretical significance of much that geology
and paleontology have provided of late towards the reformulation of our subject—
particularly the significance of mass extinction as an agent of change, and the
central role of vectorial patterns as a subject in itself. (To readers who wondered
why I treated struggle so cursorily in Chapter 2 on the essentials of Darwinian
argument, I apologize for any puzzlement, while asserting that the subject—
meriting all its traditional importance—belongs here.)
Evolutionary biologists should never lose sight of a cardinal principle linking
history and function—that historical origin and immediate utility represent
independent subjects with no necessary connection (see Chapter 11 for an extended
discussion of this principle). Struggle and competition entered the ontogeny of
Darwin's thought for a variety of reasons related to Malthus, the necessary
hecatomb for powering natural selection, views on the plenitude of nature, etc.
Struggle also serves many functions in the logic of Darwin's completed theory. But
I believe that one role may be designated as paramount. Darwin used his
distinctive views on struggle to validate the concept of progress as a cardinal
vector in the history of life. He invoked his own interpretation of struggle—in
particular, his conviction about the predominance of biotic competition—as an
"added" principle to guarantee a pattern of progress that could not be derived,
without such an auxiliary, from natural selection in its most abstract and
generalized form.
But logics of argument form webs, and no benefit accrues without a price, or
at least a set of implications. The dominance of biotic competition could validate
progress—and thus, in a vital sense, "complete" the Darwinian system. But the
adoption of such an argument required that a premise be imported from a field
external to the biological logic of selection—and such increases in the logical
complexity of theories also court danger. In this particular case, the domination of
biotic competition as a patterning agent requires