294 THE STRUCTURE OF EVOLUTIONARY THEORY
not mosaic, transmutation would be inconceivable, and would not occur precisely
for the reasons stated by Cuvier.)
In Cuvier's remarkable output of publications, three works stand out as
powerful, comprehensive documents that established professions and set a good
part of the course of 19th century biology—the 5 volume Legons d'anatomie
comparee of 1800-1805, the 4 volume Recherches sur les ossemens fossiles of
1812, and Le regne animal of 1817. The pivotal role of these three works has
always been acknowledged, but their common philosophical grounding in Cuvier's
overarching functionalism has not been adequately recorded.
The Legons of 1800-1805 arranges natural history in functional terms by
shunning the usual taxonomic order and proceeding instead by organ systems
considered in operational rather than morphological terms. Volume one treats
locomotion, functionally focused and defined ("les organes du mouvement"), while
subsequent volumes proceed through sensation, digestion, circulation, respiration,
voice, generation, and excretion.
The very first lesson, functionally organized as "considerations sur
Veconomie animale," presents the heart of Cuvier's approach. His theory of
function cannot be characterized as a crude, "democratic" adaptationism, part by
part with each item separately optimized, but rather as a more subtle, hierarchical
system that renders both structural regularities and correlations in functional terms.
Primary functions, common to all organisms, lie at the base—origin by generation,
growth by nutrition, and termination by death (see Russell, 1916, p. 31). Secondary
functions—feeling and moving—build a layer above and set the morphology of
organs for their manner of operation. These secondary, or "animal," functions, with
their neuromuscular expression, determine a yet higher level of "vital functions"—
digestive, circulatory, and respiratory, in that order. Feeling and movement require
a set of organs to hold and process food; digestion then implies a system of
distribution (circulation). Higher levels may then feed back "in a type of circle"
(Cuvier, 1805, p. 47) to influence the logically prior foundation. Power of
movement affects mode of generation and "fluide nerveux" of secondary status
flows through channels of tertiary circulation. Above all, function holds priority
and determines structure; coordination and correlation among structures records
the hierarchical ordering of interrelated functions (see particularly Cuvier, 1805,
pp. 45-60).
Cuvier states the functional foundation of his morphology in bold terms
(1805, p. 47): "The laws that determine the relationships of organs are founded
upon this mutual dependence of functions, and upon the aid that they lend to each
other. These laws have a necessity equal to laws of metaphysics and mathematics.
For it is evident that a proper harmony among organs that act upon each other is a
necessary condition of existence* for the
- Conditions d'existence became Cuvier's motto for his functionalist credo. By this
phrase, as evident in this quotation, he did not only designate adaptation to external
environment, but also coordination of parts by and for the pursuit of proper function.
Note that Darwin used Cuvier's phrase in identifying the functionalist pole of the
dichotomy (1859, p. 206, and Section 1 of this chapter).