The Fruitful Facets of Galton's Polyhedron 377
presumed phyletic stage based on ontogenetic repetition of ancestral adult stages—
see Smith, 1898, on ammonite phylogeny, for example. Thus, Hyatt's procedure,
while interestingly unconventional, scarcely lacks precedent—or consequent.)
In sum, Hyatt presents a picture of multiple lineages, evolving in parallel but
at different times (though in the same lake), through a preset sequence of stages—
with some lineages displaying an upward march to progressive characters, and
others a downward slide to regressive states of the same features. Hyatt justifies all
these claims under his old-age theory of orthogenetic unfolding: phylogenies
proceed inexorably from periods of phyletic youth and vigor, through maturity to
racial senescence and extinction. Consider a series of questions, all resolved by the
orthogenetic interpretation (and all refuting Darwinism, or any other functional
account):
- Why do the separate lineages go through similar stages? The causes cannot
reside in functional entrainment by common environmental pressures (either by
Darwinian selection or Lamarckian response to perceived needs) because the same
stages occur at different times in various lineages (same response in different
environments), while different lineages (progressive vs. regressive) often evolve
disparate forms at the same time (different response in the same environment).
Hyatt argues that the cause of parallelism must therefore be sought in an internal
shove, not an external (environmental) push:
While the perpetuation and survival of the differential characteristics can be
thus accounted for [by natural selection], we must look to other causes for
the production of the parallel forms and the regularity of succession of
these forms, as shown in the arrangement in the different series, and in the
development of the individual. This cause lies in some law of growth and
heredity which reacts against the tendency of the physical environment to
produce variations and differences, and produces parallelism in the
development of different individuals of the same species, of different
species in the same series, and in the succession of forms in the different
series, and also limits the tendency to variation within definite boundaries
in the species (1880, p. 26).- Why does the invariant series of stages follow this characteristic sequence,
with either a march to progressive features in shell size, thickness, shape and
coiling, or a fall to increasingly degenerate states of the same characters? Again, an
answer cannot be provided by functional adaptation in either the Darwinian or
Lamarckian mode, for extended regressive sequences, by their inadaptive nature,
could not then occur. Instead, this sequence of up and down marks the full scope of
the "grand potential ontogeny," defining the orthogenetic phylogeny of the entire
fauna: "Thus, we can readily understand that each of these series, whether
progressive or retrogressive, can so far as its collective life is concerned, be
compared in the closest manner with the life of an individual, and similar
correspondence be traced in both, and also that the tendencies exhibited are of two
kinds in each, one towards