1326 THE STRUCTURE OF EVOLUTIONARY THEORY
some restriction of possibilities, and does suggest some causal inferences. Raup notes
(1996), in particular, that if each species, following Darwin's explicit claims (cited at
the beginning of this chapter), pursued its own independent history of origin,
expansion, reduction and death in terms of its own special competitive prowess vs.
other unique species in singular faunas— thus implying that no general cause can
impact all species at once (or at least that such general causes only nudge, and do not
set or determine, the overall pattern)—then the kill curve, while continuing to obey
its predictable mono-tonic form, would never reach such high percentages of death in
its rarest upper episodes. Such concentration in mass extinction does imply a
coordinated cause of some sort. Raup writes (1996, p. 422):
If each genus died out independently of the others, the probability of
producing a range of from near zero to 52 percent extinction in 106 six million
year stages would be negligible. This means that pulses of extinctions of
genera must be connected in some way... because of common factors, such
as ecological interdependence or shared physical stress. We thus see a picture
of episodic extinction wherein the more intense an extinction episode, the
rarer it is. To describe extinction only as background or mass extinction, as is
commonly done, is to hide much of the structure of the extinction
phenomenon.The nonfractal tiering of time
Strict Darwinism implies continuity in the style and causal structure of change from
successive generations in populations to the waxing and waning of faunas across
geological eras. An alternate construction of time as a series of discrete tiers, or at
least of rising "regions of coagulation" that pull phenomena away from boundaries
and towards more central nucleating places —with each tier then featuring different
weights and styles, or even truly distinct modes, of causality—would seriously
challenge the crucial extrapolationist premise of Darwinian logic (the third leg on my
tripod of support). Although I know the quibbles and inconsistencies, and I recognize
that many of my neontological colleagues regard such problems as central flaws
worth a lifetime's research, I have no personal quarrel with Darwin's argument that a
vector of general progress would pervade the history of life if all scales of time record
the competitive styles of natural selection supposedly prevailing at the first tier of
anagenetic change within the history of single populations. We should therefore take
firm notice, and regard as highly paradoxical, the failure of life's history to feature
such a vector as an obvious organizing principle and predominant signal of
phylogeny.
I reject, for the most part, the Raupian solution of fractality in time, with
Darwinian inefficacy throughout. Instead, I favor the alternative view that Darwinism
basically works as advertised in its own realm at the first tier of time, but cannot
"push through" to impose its characteristic signal upon processes and phenomena of
higher tiers. Such a proposal implies a very different attitude towards time and
change—an attitude inspired and encouraged by