Punctuated Equilibrium and the Validation of Macroevolutionary Theory 1021
The right level at which to look for evolutionary trends, he [Gould] could then
claim [indeed I do], is not the level of the gene, or the organism, but the whole
species or clade. Instead of looking at the loss of particular genes from gene
pools, or the differential death of particular genotypes within a population,
look at the differential extinction rate of whole species and the differential
"birth" rate of species—the rate at which a lineage can speciate into daughter
species. This is an interesting idea ... It may be true that the best way of seeing
the long-term macro-evolutionary pattern is to look for differences in "lineage
fecundity" instead of looking at the transformations in the individual lineages.
This is a powerful proposal worth taking seriously.I am puzzled by the discordance and inconsistency, but gratified by the outcome.
Dawkins and Dennett, smart men both, seem unable to look past the parochial
boundaries of their personal interest in evolution, or their feelings of jealousy towards
whatever effectiveness my public questioning of their sacred cow of Darwinian
fundamentalism may have enjoyed (see Gould, 1997d)—so they must brand
punctuated equilibrium as trivial. But they cannot deny the logic of Darwinian
argument, and they do manage to work their way to the genuine theoretical interest of
punctuated equilibrium's major implication, the source of our primary excitement
about the idea from the start.
THE WISDOM OF AGASSIZ'S AND VON BAER'S THREEFOLD HISTORY OF
SCIENTIFIC IDEAS. When I was writing Ontogeny and Phylogeny, I came across a
wonderful, if playfully cynical, statement by the great embryologist Karl Ernst von
Baer (1866, p. 63) about Louis Agassiz's view on the ontogeny of scientific theories
(also quoted on p. 687): "Deswegen sagt Agassiz, dass wann eine neue Lehre
vorgebracht wurde, sie drei Stadien durchzumachen habe; zuerst sage man, sie sei
nicht wahr, dann, sie sei gegen die Religion, and im dritten Stadium, sie sei langst
bekannt gewesen." [Therefore, Agassiz says that when a new doctrine is presented, it
must go through three stages. First, people say that it isn't true, then that it is against
religion, and, in the third stage, that it has long been known.]
I won't vouch for the generality of this scenario, but Agassiz's rule certainly
applies to the history of nonscientific debate about punctuated equilibrium,
particularly to the aspect governed by jealousy of critics—as Eldredge and I
recognized in a previous publication entitled: "Punctuated equilibrium at the third
stage" (Gould and Eldredge, 1986). The first stage of empirical denial, extending
roughly from our original publication in 1972 to the Chicago macroevolution meeting
of 1980, featured studies of fossil sequences by paleontologists (notably Gingerich,
1974 and 1976), many of whom tried to deny that punctuated equilibrium occurred
very frequently, if at all, by documenting cases of gradualism.
During the second phase, spanning the first half of the 1980's, the primary
subject of this section, punctuated equilibrium, was vociferously dismissed as
contrary to religion—that is, as apostate anti-Darwinian nonsense. Our theory,