Internalism and Laws of Form 275
design: Radiata, Mollusca, Articulata, and Vertebrata.* Agassiz was particularly
impressed that von Baer, the century's greatest embryologist, had, independently of
Cuvier, recognized the same system by developmental standards. If morphology
and embryology coincided so well, and if the greatest students of both subjects had
reached agreement by such different criteria, then the fundamental principle of
natural order must lie revealed:
If we remember how completely independent the investigations of K. E.
von Baer were from those of Cuvier, how different the point of view was
from which they treated their subject, the one considering chiefly the mode
of development of animals, while the other looked mainly to their structure;
if we further consider how closely the general results at which they have
arrived agree throughout, it is impossible not to be deeply impressed with
confidence in the opinion they both advocate, that the animal kingdom
exhibits four primary divisions, the representatives of which are organized
upon four different plans of structure, and grow up according to four
different modes of development (1857, p. 231).But how shall taxonomists characterize the basis for this primary division into
four? As God's mind lies so far beyond our poor faculties, we cannot identify his
intent (though we can certainly record his decisions); but we may surely specify
the criteria that he did not use. Much of Agassiz's Essay features a litany of claims
in this negative mode: as only two alternatives exist, any argument against
production of form by physical laws (a mode of origin that would induce a
functional correlation of morphology and environment on the broadest scale) must
provide support for the organization of relationships as categories of divine will
and thought. After an introductory chapter, for example, the first two sections of
Agassiz's Essay present a contrast with a common intent. How can physical laws
simply produce the "best" solution for each particular circumstance if (1) identical
environments house creatures of all four great body plans, and if (2) each of the
body plans manages to inhabit all major environments? Agassiz summarizes: "The
simultaneous existence
- Agassiz stuck resolutely to this system until his dying day, despite collapsing
evidence, particularly for the union of Coelenterata and Echinodermata within the Radiata (a
subject of much personal research by Agassiz). His last, posthumous article, "Evolution and
Permanence of Type" (1874), mounts an attack on Darwin from the perspective of this four-
fold taxonomy. A good deal of filial piety must lie behind Agassiz's loyalty, for Cuvier, at
the end of his life, had befriended the young and inexperienced Swiss naturalist, and even
passed on to Agassiz the project that would assure his later fame—a monograph of all fossil
fishes. This union also includes a powerful irony, for Cuvier was the most prominent of all
functionalist thinkers, and Agassiz uses their shared taxonomic framework as an ultimate
defense of formalism. But the richness of great and expansive systems (like Cuvier's) allows
such multiplicity of use and interpretation—and sets the curious phenomenon of strange
bedfellows, both in politics and intellectual life. Cuvier fancied himself as a committed
empiricist. He took the quadripartite system (so amenable to formalist interpretation) as a
"given" not particularly subject to analysis at all, and he then lavished his functionalist
interpretations on the myriad modifications for adaptive purpose within each plan.