1008 THE STRUCTURE OF EVOLUTIONARY THEORY
begin modestly and expand outward thereafter. (In this sense, punctuated equilibrium
has grown in theoretical scope, primarily as macroevolutionary theory developed and
became better integrated with the rest of evolutionary thought—and largely through
articulation of the hierarchical model, as discussed in the previous chapter).
We started small as a consequence of our ignorance and lack of perspective, not
from modesty of basic temperament. As stated before, we simply didn't recognize, at
first, the interesting implications of punctuated equilibrium for macroevolutionary
theory—primarily gained in treating species as Darwinian individuals for the
explanation of trends, and in exploring the extent and causes of stasis. With the help
of S. M. Stanley, E. S. Vrba and other colleagues, we developed these implications
over the years, and the theory grew accordingly. But we never proposed a radical
theory for punctuations (ordinary speciation scaled into geological time), and we
never linked punctuations to microevolutionary saltationism.
Of course we made mistakes—serious ones in at least two cases—and the theory
has changed and improved by correcting these errors. In particular, and as
documented extensively in Chapter 8, we were terribly muddled for several years
about the proper way to treat, and even to define, selection at the level of species—
the most important of all theoretical spinoffs from punctuated equilibrium. We
confused sorting with selection (see Vrba and Gould, 1986, for a resolution). We also
did not properly formulate the concept of emergence at first; and we remained
confused for a long time about emergence of characters vs. emergence of fitness as
criteria for species selection (Lloyd and Gould, 1993; Gould and Lloyd, 1999). In
retrospect, I am chagrined by the long duration of our confusion, and its expression in
many of our papers. But I think that we have now resolved these difficult issues.
Secondly, as discussed on pages 796-798, I think that we originally proposed an
incorrect reason for the association of rapid change with speciation. But I believe that
we portrayed the phenomenology correctly, and that we have, with the help of
Futuyma's (1987) suggestions, now developed a proper explanation. Thus, the theory
of punctuated equilibrium has altered substantially to correct these two errors.
Interestingly (and ironically), however, these important changes do not figure at all in
the deprecating claims of the urban legend about our supposed retreats and
chameleon-like redefinitions—for our detractors hardly recognize the existence of
punctuated equilibrium's truly radical claim for evolutionary theory: its implications
for selection above the species level, and for the explanation of trends.
Punctuated equilibrium, in short, has enjoyed true Darwinian success through
the years: it has struggled, survived, changed and expanded. But the theoretical
evolution of punctuated equilibrium belongs to the sphere of cultural change with its
Lamarckian mode of transmission by direct passage of acquired improvements. Thus,
the theory need not remain in Darwinian stasis, but may grow—as it has—in (gulp!) a
gradualist and progressive manner.
The saltationist canard has persisted as our incubus. The charge could never be
supported by proper documentation, for we never made the link or