214 THE STRUCTURE OF EVOLUTIONARY THEORY
but such a process does produce internal order within a body by struggle— just as
natural selection engenders the external harmonies of adaptive design and
ecological balance: "As the struggle of parts [Kampf der Theile] yields
purposefulness within an organism ... so does the analogous struggle for existence
[Kampf urn's Dasein] among individuals yield purposefulness with respect to
external conditions of existence" (Roux, 1881, p. 238). Roux also echoed Darwin's
most general and most important philosophical principle:
To many, the direction of this book may well seem very strange—for it
holds that, in an animal, in which everything is so exquisitely ordered, in
which all the different parts interlock with such excellence, and work to-
gether in such perfected coordination, that a struggle of parts occurs, so that
in one place, where everything works together according to firm principles,
a conflict among the individual parts exists. But how can an entity [ein
Games] exist, whose parts are at variance? ... How shall the good and the
stable arise from struggle and battle?... All good can only arise from
struggle [alles Gute nur aus dem Kampfe entspringt] (1881, p. 64).Darwin himself could not have penned a better epitome for his most radical
claim.
GERMINAL SELECTION AS A HELPMATE TO PERSONAL
SELECTIONWeismann proposed the theory of germinal selection as a logical solution to the
problem of degeneration in a non-Lamarckian world. But germinal selection only
makes sense under Weismann's concept of inheritance—yet another theory of
structural hierarchy, and explicitly linked by Weismann to Haeckel's 6-fold
sequence as a further breakdown and elaboration (for germ plasm) of categories
within Haeckel's lowest unit of "plastids," or cellular constitutents (1896, p. 42).
In Weismann's admittedly hypothetical system, the fundamental sub-
microscopic particles of heredity are called "biophors." Biophors aggregate to
"determinants," the key unit for the theory of germinal selection. The logic of
panselectionism requires a high degree of easy dissociability among genetic
"particles" responsible for "traits" that can be individually optimized to construct
well-adapted organisms—for if "particles" become too tightly linked or
coordinated, then each change entails too many consequences for other traits, and
constraints begin to prevail over adaptation. "Determinants" play this necessary
role in Weismann's panselectionist theory of heredity. Each determinant builds an
organ or a particular part of the body—in other words, an "item" of the phenotype
that selection can mold independently.
Determinants, like their constituent biophors, are invisible and hypothetical.
They aggregate into the first observable unit, the "id"—an earlier use of a term that
Freud coopted for a much different role and purpose (just as paleontologists had
coined and developed a meaning for "mutation" (Waagen, 1869) before the new
science of genetics outcompeted us with a later and altogether