The Fruitful Facets of Galton's Polyhedron 463
have now presented to you examples of both states of mind: First, a bit of
skepticism with regard to the role which the formation of geographic races
or subspecies may have played in evolution; and then a bit of optimism in
trying to show that the physiological system underlying orderly
development, on the basis of the genetic constitution, allows some of the
larger steps in evolution to be understood as sudden changes by single
mutations concerning the rate of certain embryological processes (1933, p.
546).This quotation would work as full jacket copy for Goldschmidt's later book—
except for one omission. The quotation contains no statement at all, about systemic
mutations or the attempt to construct a revolutionary, holistic genetics by denying
the corpuscular gene. In other words, Goldschmidt developed the full intellectual
framework of his argument for the strict separation of micro- and macroevolution,
and for the saltational basis of macroevolution, by invoking the developmental
theme alone—that is, before he initiated his campaign for a revolutionary genetics
(beginning in the late 1930's, and then continuing and intensifying to his death).
The developmental theme enjoys both temporal priority and complete sufficiency.
Goldschmidt devised the hopeful monster (both the term and concept) before he
ever formulated his radical genetics. Moreover, the developmental theme can carry
the argument for saltational macroevolution all by itself. This conclusion, I think,
resolves the puzzle of textual confusion in The Material Basis of Evolution.
Goldschmidt had constructed his outline by 1933, based on the developmental
theme alone. He began to formulate his radical genetics later, and then interpolated
this material into a structure already established. These interpolations often seem
hasty or haphazard, and Goldschmidt's chapters on systemic mutation do not
always cohere with the earlier material. Ironically, the passages on systemic
mutation in The Material Basis work much like an ordinary "hopeless monster" in
the organic world. They do not mesh with the coherent outline or developmental
program of a book planned and coordinated long before!
In introducing the developmental theme to carry his ideas on macroevolution,
Goldschmidt (1933, p. 543) states that biologists have long recognized the need to
understand the genetic basis and selective advantage of major evolutionary
changes—but that a crucial third component has been missing: "But there is a third
point, often neglected, which lies, I think, at the basis of the whole problem,
namely, the nature of the developmental system of the organism which is to
undergo evolutionary change." Goldschmidt then argues that his
macroevolutionary ideas arose "as a logical consequence of my views on gene
controlled development" (p. 544), with a key in the concept of alterations in rate:
"The most probable mutational change with a chance to lead to a normal organism
is a change in the typical rate of certain developmental processes" (p. 544). He then
praises D'Arcy Thompson for locating the phyletic meaning of these ideas in small
mutational changes in rates, operating early in development to yield a saltational
origin of new adult