960 THE STRUCTURE OF EVOLUTIONARY THEORY
subject, see also Loch, 1999, on "A Punctuated equilibrium model of technology
diffusion.")
The development of improved systems for human communication in the past
century must represent one of the most goal-directed and clearly progressionist
sequences identifiable in either the human or natural sciences— hence the apparent
consonance with gradualist models, and the unpromising character, at first glance,
of punctuationalist alternatives. But Mokyr defends a punctuational reformulation
by centering his descriptions and explanations on a comparison of stages in this
technological trend with the discrete origin of biological species as genuine
entities, and then citing punctuated equilibrium for emphasizing this theme as a
reform within Darwinian biology (Mokyr, 1990, p. 351).
While not denying the clearly goal-oriented and progressive nature of the
trend—and while also (along with Gersick) noting the Lamarckian capacity of
human culture to change directionally and incrementally within plateaus, but also
stressing the qualitative differences between this limited gradualism and the much
larger and quicker transitions of goal-directed punctuations— Mokyr (p. 354)
describes the basic outline of this history as four stages separated by punctuational
breaks. He also, again as with Gersick, stresses the nonpredictability of outcomes,
and then notes, continuing the analogy with speciation, that punctuational models
enjoin the study of particular conditions favorable to leaps of change, an issue that
does not arise in explanations based upon gradualistic anagenesis:
Long-distance communications thus illustrate the abruptness of
technological change. There was no natural transition from semaphore to
the electrical telegraph, or a gradual movement from the telegraph to the
first radio transmission by Marconi in 1894, nor a smooth natural
development from the long-wave radio used in the first thirty years to the
shortwave systems of the later 1920s. Each of the three systems was
subsequently perfected by a long sequence of microinventions, but these
would not have occurred without the initial breakthroughs. Their concept
was novel, they made things possible that were previously impossible, and
they were pregnant of more to come. Therein lies the essence of a
macroinvention.... Many macroinventions, just like the emergence of
species, were the result of chance discoveries, luck, and inspiration.
Biologists agree that certain environments are more conducive to speciation
than others.Just as for technological change, we tend to view the history of scientific
ideas on particular subjects as, in principle, the most incrementally progressionist
of all human activities by the empiricist paradigm of ever-closer approximation to
natural truth through objective accumulation of data under unchanging principles
of "the scientific method"—an idea famously challenged by Kuhn (1962) in the
most influential punctuationalist theory in 20th century scholarship—see p. 967.
Thus, punctuationalist reformulations in this domain tend to strike people as
especially surprising. The distinguished