382 THE STRUCTURE OF EVOLUTIONARY THEORY
leads at once to the question, what are the limits within which a species
may vary? ... The limits of variation in the species have been found to
correspond to the growth changes in an individual (1880, p. 20).Hyatt viewed his orthogenetic theory as a contribution to the larger vision of
19th century mechanistic science—a hope that when we finally learn the laws of
heredity and discover the principles of biased variability, then evolution shall
become as predictable as ontogeny: "In all cases the individual and its series must
change by growth along certain lines of modification, which it is but reasonable to
suppose we shall someday be able to map out beforehand for a series of forms with
the same precision that we can now forecast the metamorphoses of any individual
in a given species" (1880, p. 18). Charles Darwin, who understood the contingent
character of history, could not have disagreed more forcefully.
Hyatt's hardline version of orthogenesis offered no quarter for fruitful
interaction with Darwinism. If all structuralist and formalist thinking, and all
theories of channeled variation, existed only (and in principle) in this adversarial
mode, then the important 19th century debate on orthogenesis could teach us little
today. But my account of Eimer's orthogenetic theory has already illustrated the
potential for useful interaction between internal orthogenesis and external
adaptation—even though Eimer chose Lamarck rather than Darwin for the basis of
his functionalist component. I shall next present the even more accommodating
version of C. O. Whitman, to illustrate a maximal contrast with Hyatt, and to
emphasize the possibility of Darwinian insight from orthogenesis.
Kurt Vonnegut introduced the useful word "karass" to describe groups of
people who may not explicitly interact, or even know each other, but whose lives
seem tied together by action and circumstance. Hyatt and Whitman (who did, in
fact, know each other well) must have belonged to the same karass. Both studied
under Louis Agassiz. (Hyatt spent his career in the Boston area, worked primarily
on ammonites, and occupied the office that I now inhabit at the Museum of
Comparative Zoology.) Both participated in the early days of summer courses in
New England natural history and marine biology (Whitman studied with Agassiz
on Penikese Island; Hyatt ran a teacher's school of natural history in Annisquam).
Both men rank as the two key figures in the early days of the Marine Biological
Laboratory at Woods Hole, Hyatt as first president of the board of trustees,
Whitman as first director. Both devoted their major research efforts to formulating
theories of orthogenesis, Hyatt with ammonites and snails, Whitman with pigeons.
But their orthogenetic theories could not have differed more profoundly,
particularly in their divergent attitudes toward complementarity with Darwinism.
In understanding why the adversarial Hyatt reached a dead end, and in grasping the
insight offered by the accommodating Whitman (who, for unfortunate historical
reasons, gained very little historical impact for his orthogenetic views), we may
better appreciate both the blind alleys and the vital themes of