570 THE STRUCTURE OF EVOLUTIONARY THEORY
fifty years later at the Origin's centennial in 1959. The success of the Modern
Synthesis established the difference. Beginning as a pluralistic marriage of Darwin
and Mendel in the 1930's, the Synthesis had hardened by 1959 into a set of core
commitments that, at least among epigones and acolytes, had become formulaic
and almost catechistic, if not outright dogmatic.
Again, I will consider two leading Festschriften of this later centennial, the
two major American celebrations in this case: the American Philosophical
Society's annual general meeting in Philadelphia, and the elaborate festival held in
Chicago in 1959 (published as a three volume compendium, edited by Sol Tax, in
1960). Major speakers at both meetings attributed the remarkable uniformity of
opinion on all major issues to the success of the Synthesis, particularly to a
consensus on the paramount, virtually exclusive, role of natural selection as the
cause of evolutionary change. Ledyard Stebbins, appropriately for the City of
Brotherly Love, spoke in Philadelphia about the unifying power of natural
selection: "The last quarter of the century which has elapsed since the publication
of The Origin of Species has seen the gradual spread and an almost universal
acceptance by biologists actively working with problems of evolution of some
form of the neodarwinian concept of evolutionary dynamics. This concept may be
broadly defined as one which, like Darwin's original concept, maintains that the
direction and rate of evolution have been largely determined by natural selection"
(Stebbins, 1959, p. 231). Meanwhile, in Chicago, Julian Huxley gave a capsule
history of Darwinism, ascribing the same binding role to natural selection: "The
emergence of Darwinism, I would say, covered the fourteen-year period from 1859
to 1872; and it was in full flower until the 1890's, when Bateson initiated the anti-
Darwinian reaction. This in turn lasted for about a quarter of a century, to be
succeeded by the present phase of Neo-Darwinism, in which the central Darwinian
concept of natural selection has been successfully related to the facts and principles
of modern genetics, ecology, and paleontology" (Huxley, 1960, p. 10).
Michael Lerner's development of the argument (in the Philadelphia
symposium) may be viewed as typical for this confident time. He begins with the
venerable (if cryptic) motto of the Greek poet Archilochus: "The fox knows many
things, but the hedgehog knows one big thing." As a profession, Lerner states, we
marched along the path from Darwin to the Modern Synthesis as urchins,
following the "one big thing" of natural selection, and ultimately rejecting the
major alternatives as "sins against Occam's razor." Lerner wrote:
Their one big thing, natural selection, set at rest the doctrine of special
creation. In combination with our knowledge of Mendelian inheritance
acquired since Darwin's day, it rendered obsolete such alternative theories
of evolution as were based on extra-mechanical agencies, or on direct
adaptation of organisms to their immediate environment (that is, on
inheritance of acquired characters), and exposed them as sins against
Occam's razor. Natural selection furnished the binding principle for a
general or unified theory of historical change in the living world (Lerner,
1959, p. 173).