Punctuated Equilibrium and the Validation of Macroevolutionary Theory 761
the primary signal of the fossil record as valuable information rather than
frustrating failure. We therefore began our original article (Eldredge and Gould,
1972) with a philosophical discussion, based on work of Kuhn (1962) and Hanson
(1961), on the necessary interbedding of fact and theory. We ended this
introductory section by writing (1972, p. 86):
The inductivist view forces us into a vicious circle. A theory often compels
us to see the world in its light and support. Yet we think we see objectively
and therefore interpret each new datum as an independent confirmation of
our theory. Although our theory may be wrong, we cannot confute it. To
extract ourselves from this dilemma, we must bring in a more adequate
theory; it will not arise from facts collected in the old way ... Science
progresses more by the introduction of new world-views or "pictures" than
by the steady accumulation of information... We believe that an
inadequate picture has been guiding our thoughts on speciation for 100
years. We hold that its influence has been all the more tenacious because
paleontologists, in claiming that they see objectively, have not recognized
its guiding sway. We contend that a notion developed elsewhere, the theory
of allopatric speciation, supplies a more satisfactory picture for the ordering
of paleontological data.The paradox of stymied practice
This second paradox cascades from the first. If a theory—geologically insensible
gradualism as the anticipated expression of evolution in the fossil record, in this
case—can insulate itself against disproof from within by defining contrary data as
artifactual, then proper assessments of relative frequencies can never be
achieved—for how many scientists will devote a large chunk of a limited career to
documenting a phenomenon that they view as a cardinal restriction recording a
poverty of available information?
Paleontological studies of evolution therefore became warped in a lamentable
way that precluded any proper use of the fossil record, but seemed entirely
honorable at the time. We practitioners of historical sciences, as emphasized
throughout this book, work in fields that decide key issues by assessment of
relative frequencies among numerous possible outcomes, and only rarely by the
more "classical" technique of "crucial experiments" to validate universal
phenomena. Therefore, any method that grossly distorts a relative frequency by
excluding a common and genuine pattern from consideration must seriously stymie
our work. When traditional paleontologists eliminated examples of abrupt
appearance and stasis from the documentation of evolution, they only followed a
conventional precept—for they believed that both patterns recorded an artifact of
imperfect data, thus debarring such cases from consideration. The relative
distributions of evolutionary rates would therefore emerge only from cases of
gradualism—the sole examples judged as sufficiently data-rich to record the
process of evolution in adequate empirical detail. But this project could not even
succeed in its own terms, for gradualism occurs