460 THE STRUCTURE OF EVOLUTIONARY THEORY
as a quantitative phenomenon produced by a balance of male and female sex
determiners. He produced a series of graded intersexes by altering these balances
experimentally. At a time (between 1910 and 1920) when the great majority of
geneticists focused their work upon basic principles of transmission, Goldschmidt
had already begun to study gene function and development—in order to establish a
profession that he called "physiological genetics." He recognized that genes work
by controlling the rates of chemical processes. Normal development requires a
proper balance and definite timing of substances; evolutionary change occurs by
alteration in the timing of development. Goldschmidt initiated and extended the
concept of "rate genes," and the germ of the hopeful monster clearly lies within
this crucial concept of his career.
This work also led Goldschmidt to what many scientists regard as his most
enduring contribution—the naming and characterization of "phenocopies." If genes
affect timing, then experimental manipulations of temperature and chemical
environment might induce changes identical with those found in mutants, thus
confirming the rate hypothesis. Goldschmidt produced such "mutant" phenotypes
without mutations and christened them "phenocopies." He maintained great
fondness for this subject and for his discoveries in this area. Indeed, the very last
words of his posthumously published autobiography (1960, p. 326) do not proffer
cosmic advice, but merely state: "It is my greatest intellectual happiness that I can
still work in my laboratory and even make interesting discoveries in the field of
chemically induced phenocopies."
Goldschmidt's later apostasy on macroevolution may be traced to this
personal source in his early work on development, particularly to his early
recognition that small genetic changes, operating early enough in ontogeny, may
engender cascading effects towards a large phenotypic jump in a single genetic
step.
- The very term "hopeful monster," and the form of evidence adduced by
Goldschmidt in support, establishes the developmental theme as primary. Why did
Goldschmidt use such an odd term at all, an apparently flippant phrase (and,
therefore, a poor rhetorical strategy for pushing heterodox views) almost
guaranteed to generate rebuke from upholders of orthodox (and dull) academic
prose? In part, of course, the term began in whimsy, and then flowed too far on
winds of circumstance. Goldschmidt recalled in his autobiography (1960, p. 318):
"I spoke half jokingly of the hopeful monster in my first publication on the
subject." But, in another sense, the term could not have been more apt or
appropriate once one recognizes that ontogenetic development—not systemic
mutation—undergirds the concept.
What makes a monster hopeful? Goldschmidt identifies two necessary and
sufficient conditions:
(1) The mutant must, by good fortune, be well fitted for a particular,
previously unexploited environment in its vicinity—the Darwinian, or functional
theme. A mutant rat with fused tail vertebrae is just a monster; a proto-bird, with
feathers better positioned for flight as a fortuitous consequence of a similar fusion,
becomes a hopeful monster. An ordinary nektonic teleost fish with