Species as Individuals in the Hierarchical Theory of Selection 641
the same kind of explanation. The gene-based view works best for bookkeeping,
while the organism-based view represents one legitimate level of causality—the
one regarded as effectively ubiquitous and exclusive by Darwin himself. In this
sense, both views are valid; but they are not comparable—and genes vs. organisms
do not represent alternatives on an identical playing field of common explanatory
intent.
Moreover, Dawkins's shift from the selfish gene to the extended phenotype
does not reflect a simple extension or elaboration of a consistent and developing
viewpoint. He tries to save face with such a portrayal, but his strategy fails. The
conventionalism of The Extended Phenotype negates and denies the explicit
defense of gene selectionism as an empirical reality, as presented in The Selfish
Gene. Dawkins's first book says, in no uncertain terms (see quotation on page 618),
those genes are exclusive units of selection (or causal agents), and that bodies, as
passive lumbering robots, cannot play such a role. The second book says that we
can view evolution equally well from either the gene's or the organism's point of
view, that Dawkins still prefers genes, but that others remain free to favor bodies
with just as much claim to empirical adequacy. The disparate logic of these two
formulations precludes their interpretation as developing versions of the same view
of life, and one theory is not a subtler extension of the other. These two positions
connote logically contrasting, and mutually exclusive, accounts of causality in
evolution. I do not happen to regard either as correct, but I think we can all agree
that Dawkins's later view of the extended phenotype derails and controverts his
earlier defense of gene selectionism as nature's true way.
I do not know why Dawkins altered his view so radically. But may I suggest
that he simply could not—because no one can after a proper analysis of the basic
logic of the case—maintain full allegiance to the fallacious argument of strict gene
selectionism. Dawkins tried hard in 1976, but ultimately needed to make so many
statements from the organism's point of view that he must have begun to wonder
whether he could really continue to regard such organismal language as a mere
convenience, while touting the genie formulation as a unique reality. Perhaps he
finally decided that if organism-based language seemed so stubbornly ineluctable,
then organism-based causality might be equally inevitable, at least as a legitimate
option. With such an admission, the selfish gene becomes an impotent meme.
WILLIAMS'S CODICAL HIERARCHY. Williams's epochal book of 1966 set the
intellectual basis for gene selectionism, and may justly be called the founding
document for this ultimate version of Darwinian reductionism. But by 1992,
Williams had realized that interactors, and not replicators, constitute units of
selection, or causal agents in the usual sense of the term—and that hierarchy must
hold because no level of interaction can be deemed exclusive, or even primary.
Williams, however, did not wish to abandon his old apparatus for viewing genes as
fundamental and preferred units of selection. But que faire? Genes are replicators
in their only universal role (they can also