The Fruitful Facets of Galton's Polyhedron 393
washout—but natural selection encountered and preserved this pattern by mere
good fortune and must eventually let go:
It is here that we may with some reason suspect the intervention of natural
selection. It would, in this case, come in, not as a primary factor to originate
a new character, but adventitiously, by invitation, as it were, of favoring
predeterminations and environmental conditions.... The ornamental value of
these few chequers and their utility as recognition marks would obviously
be enhanced by their isolation in a plain ground, just as a few trees,
concealed in a large forest, become conspicuous when left standing alone.
These chequers, being on the larger feathers, would have the advantage of
size, and so their preeminence, attained without the aid of natural selection,
would be an open door through which it might enter and contribute to their
improvement. The part possibly taken, however, could at most be but a late
and inconsiderable share of the total achievement summed up in these
spots; and the course of events in at least one of the allied forms...
indicates that these marks are destined to be washed out (1919, p. 56).(Note, once again, the literary theme that authors often reveal their basic
commitments, probably quite unconsciously, in their choice of words. In this
statement, Whitman refers to natural selection as an "intervention"—an externality
imposed upon the essential process of orthogenesis.)
Nonetheless, Whitman does acknowledge exceptions. In one case (but only
here), he does allow that selection may have reversed, albeit in a minor way, the
orthogenetic sequence. He notes that iridescence heightens the value of color in
adaptive display. Iridescent spots become unusually conspicuous and potentially
useful—so much so, that selection may actually strengthen them against the
orthogenetic tide. Thus, when the independent trait of iridescence becomes
conjoined with pigmentation, the orthogenetic sequence can be meaningfully
impacted by selection. (Whitman properly uses his own criteria, as previously
discussed, to gauge the importance of this exception. Juvenile plumages, in this
case, develop less conspicuous spotting than adult feathers—so the ontogenetic
path belies the orthogenetic sequence): "Iridescence thus appears to be a
phenomenon tending to elevate the spots and bring them within the sphere of
utility. It seems not only to put a check upon the reduction of pigment, but also to
actually turn the tide in the opposite direction, for the reduction in this region is not
carried so far in the old as in the young male and female, as we shall presently see.
As the acquisition of metallic brilliancy is accompanied by an exceptional love of
display in the male, the chief directing factor in its development may well be
natural selection" (1919, p. 43).
These statements might lead a modern evolutionist to view Whitman's
orthogenesis as irrelevant to current debates (if not risible in any context). But if
Whitman did not come to praise Darwin, he did not write to bury the founding
father either. Within his chosen context of primacy for the orthogenetic pathway,
Whitman sought a maximal and fruitful interaction with