Species as Individuals in the Hierarchical Theory of Selection 619
Now they go by the name of genes, and we are their survival machines
(1976, p. 21).One might dismiss this rhetorical flourish as harmless enthusiasm. But we
must also recognize that, however extended the metaphors, Dawkins's images do
accurately express his false theory of selective agency—for if genes can be
depicted as exclusive units of selection, then they become the causal agents of
evolution; and if bodies are Darwinian ciphers both for their transiency and by
their lethargy relative to the "lean and mean" genes living within, then bodies
might as well be described as inert and manipulated repositories ("lumbering
robots").
Dawkins writes in his introduction (1976, p. ix): "We are survival machines—
robot vehicles blindly programmed to preserve the selfish molecules known as
genes. This is a truth, which still fills me with astonishment. Though I have known
it for years, I never seem to get fully used to it." I can only regard this honest
admission as a striking example of the triumph of false consistency over legitimate
intuition.
Sieves, plurifiers, and the nature of selection: the rejection of
replication as a criterion of agency
The linkage of selective agency to faithful replication has been urged with such
force and frequency that the argument now functions as a virtual mantra for many
evolutionary biologists. But when we consider the character of natural selection as
a causal process, we can only wonder why so many people confused a need for
measuring the results of natural selection by counting the differential increase of
some hereditary attribute (bookkeeping) with the mechanism that produces relative
reproductive success (causality). Replicators cannot be equated with causal agents
(unless they also happen to be interactors, for only interactors can be agents). Units
of selection must be actors within the guts of the mechanism, not items in a
calculus of results.
Genes struck many people as promising units for a twofold reason that does
record something of vital evolutionary importance, but bears little relationship to
the issue of selective agency. Persistence and replication do lie among the
necessary (but not sufficient) criteria for calling any biological entity an
evolutionary individual. Since evolution requires hereditary passage, and since
genes transmit faithful copies of themselves, and also represent the smallest
functional unit of physical continuity between generations of sexual organisms (the
kind of individuals we know best for obvious parochial reasons), many biologists
assumed that genes must therefore act as the basic (or even the only) unit of
selection.
This interesting error arises from two common fallacies in human reasoning:
THE CONFUSION OF NECESSARY WITH SUFFICIENT CONDITIONS. We all agree
that units of selection must be evolutionary individuals in Darwinian theory—and
that status as an evolutionary individual depends upon a set of criteria discussed on
pages 602-613. These criteria do include hereditary