The Fruitful Facets of Galton's Polyhedron 433
Just as the establishment of Linnaean species had made genera artificial, so
too does the recognition of de Vriesian elementary species relegate the con-
ventional Linnaean species to a congeries with no natural status. De Vries argues
that this theoretical progress from larger to successively smaller units of natural
"reality" illustrates the general advance of science as a reductionistic enterprise. A
"stepping down" from the Linnaean species to the de Vriesian elementary species
can claim both the sanction of history and the virtue of utility: "What is to guide us
in the choice of the material? The answer may only be expected from a
consideration of elementary species. For it is obvious that they only can be
observed to originate, and that the systematic species, because they are only
artificial groups of lower unities, can never become the subject of successful
experimental inquiry" (1905, p. 517).
This redefinition of species as discontinuous saltations inevitably raised the
issue of whether de Vries' new units ("elementary species," or "jordanons" of other
terminologies) always originated from single monophyletic sources, or represented
discrete phenotypes that could arise more than once—thus divorcing this
supposedly "most real" taxon from the usual genealogical criterion of monophyly
for a basic unit in a phylogenetic system. De Vries, following both the logic of his
argument and his observation that elementary species of Oenothera arose again
and again, accepted the implication (so strange to modern "population thinking"
and genealogically based taxonomy) that the same species could, and usually did,
arise many times. In fact, such a propensity for multiple origins established a major
criterion for potential success. De Vries noted as central to his concept (1909a, p.
208) "the assumption that the new form or species does not arise merely once from
the parent species but ... a great many times and with some degree of regularity."
De Vries devised an interesting set of subtypes for his saltations—thus
revealing another aspect of the philosophical complexity of his ideas (not always
expressed with consistency, but often replete with interesting psychological and
sociological influences). If "stepping down" from the linneon to the jordanon
revealed a reductionist bias usually interpreted as "modernist" in his time, then de
Vries's classification of mutations reveals an allegiance to notions of progress and
regress that might be deemed archaic in its implied fascination for the scala
naturae.
De Vries recognized some of his mutations as starkly different (in a
qualitative sense) from the parental form. But others could be linked in a series,
with the parent as prototype, either by loss of ancestral characters or by simple
quantitative alteration. All categories included equally "good" species in the causal
or genetic sense—that is, equally discontinuous entities, formed suddenly without
intermediates, and true breeding under self-fertilization. But only the first category
established genuine novelty in evolution; thus, only these truly different species
contributed to the progress of life's history. All other categories comprised
variations on parental forms (usually based on loss or diminution of characters),
and could only constitute a series around the parental prototype. Therefore, in the
oldest taxonomic ploy of evolutionary