After all, the notion of a general anatomical blueprint that contains all
particular incarnations by acting as a fundamental building block (Goethe's leaf or
Geoffroy's vertebra) moved long ago from conceptualization as a disembodied and
nonmaterial archetype employed by a creator, to an actual structure (or inherited
developmental pathway) present in a flesh and blood ancestor—a material basis for
channeling, often in highly positive Ways, the future history of diversity within
particular phyletic lineages. This switch from archetype to ancestor permitted us to
reformulate the idea of "essence" as broad and fruitful commonalities that unite a
set of particulars into the most meaningful relationships of common causal
structure and genesis. Our active use of this good word should not be hampered by
a shyness and disquietude lacking any validity beyond the vestiges of suspicions
originally set by battles won so long ago that no one can remember the original
reasons for anathematization. Gracious (and confident) victors should always seek
to revive the valid and important aspects of defeated but honorable systems. And
the transcendental morphologists did understand the importance of designating a
small but overarching set of defining architectural properties as legitimate essences
of systems, both anatomical and conceptual.
Hull correctly defines theories as historical entities, properly subject to all the
principles of narrative explanation—and I shall so treat Darwinian logic and its
substantial improvements and changes throughout this book. But theories of range
and power also feature inherent "essences," implicit in their logical structure, and
operationally definable as minimal sets of propositions so crucial to the basic
function of a system that their falsification must undermine the entire structure, and
also so necessary as an ensemble of mutual implication that all essential
components must work in concert to set the theory's mechanism into smooth
operation as a generator and explanation of nature's order. In staking out this
middle Goldilockean ground between (1) the "too little" of Hull's genealogical
continuity without commitment to a shared content of intellectual morphology and
(2) the "too much" of long lists of ideological fealty, superficially imbibed or
memorized, and then invoked to define membership in ossified cults rather than
thoughtful allegiance to developing theories, I will argue that a Darwinian essence
can be minimally (and properly) defined by three central principles constituting a
tripod of necessary support, and specifying the fundamental meaning of a powerful
system that Darwin famously described as the "grandeur in this view of life."
I shall then show that this formulation of Darwinian minimal commitments
proves its mettle on the most vital ground of maximal utility. For not only do these
three commitments build, in their ensemble, the full frame of a comprehensive
evolutionary worldview, but they have also defined the chief objections and
alternatives motivating all the most interesting debate within evolutionary theory
during its initial codification in the 19th century. Moreover, and continuing in our
own time, these three themes continue to specify the major weaknesses, the places
in need of expansion or shoring up, and the locus of unresolved issues that make
evolutionary biology such a central and
12 THE STRUCTURE OF EVOLUTIONARY THEORY