Defining and Revising the Structure of Evolutionary Theory 89
diminishing, but equally random and sudden, effects at all scales, as proposed in
Raup's "field of bullets" model.)
- In a paradoxical epilogue, I argue (despite my role as a longtime champion
of the importance and scientific respectability of unpredictable contingency in the
explanation of historical patterns) that the enlargement and reformulation of
Darwinism, as proposed in this book, will recapture for general theory (by adding a
distinctive and irreducible set of macroevolutionary causes to our armamentarium
of evolutionary principles) a large part of macroevolutionary pattern that Darwin
himself, as an equally firm supporter of contingency, willingly granted to the realm
of historical unpredictability because he could not encompass these results within
his own limited causal structure of strict reliance upon smooth extrapolation from
microevolutionary processes by accumulation through the immensity of geological
time.
A FINAL THOUGHT. May I simply end by quoting the line that I wrote at the
completion of a similar abstract (but vastly shorter, in a much less weighty book)
for my first technical tome, Ontogeny and Phylogeny (1977b, p. 9): "This epitome
is a pitiful abbreviation of a much longer and, I hope, more subtle development.
Please read the book!"