Seeds of Hierarchy 181
of physical fluids would build the increasing complexity of anatomy. He held that
the products of spontaneous generation arose as small, soft and un-differentiated
primal forms. The complexifying force—which Lamarck usually called le pouvoir
de la vie or la force qui tend sans cesse a composer I'organisation—resides in the
motion of fluids and their inevitable tendency to carve channels, sacs, and
passageways in soft tissues. This process, extended through time, gradually builds
ever greater complexity. In the Histoire naturelle of 1815, Lamarck offers his most
explicit statement about this process: "As the movement of fluids... accelerates,
the vital forces would grow proportionately, and so will their power. The rapid
motion of fluids will etch canals between delicate tissues. Soon their flow will
begin to vary, leading to the emergence of distinct organs. The fluids themselves,
now more elaborate, will become more complex, engendering a greater variety of
secretions and substances composing the organs" (1815, in Corsi, 1988, p. 189).
Lamarck did clearly assert that these internal carvings of complexity main-
tained a relentless and intrinsic causal basis separate from the apparatus of
response to "felt needs" used in building adaptations to changing local
environments. He contrasted the two sets of forces in writing: "There exists a
variety of environmental factors which induces a corresponding variety in the
shapes and structure of animals, independent of that special variety which
necessarily results from the progress of the complexity of organization in each
animal" (1809, p. 112). He also stated that the entire escalator of complexity could
run a full course in a constant environment: "If nature had given existence to none
but aquatic animals and if all these animals had always lived in the same climate,
the same kind of water, the same depth, etc., etc., we should then no doubt have
found a regular and even continuous gradation in the organization of these
animals" (1809, p. 69).
Lamarck therefore proposes two distinct sets of forces to construct what he
regarded as the two preeminent features of life—progress in linear order, and
adaptation to environment. The interactions of these sets—not the causes or
properties of either one—establish the foundation of Lamarckism, properly defined
in his own expansive terms.
Distinctness of the two sets
I shall argue in the next section that these two sets of concepts must be regarded as
both logically distinct and opposed in Lamarck's system. My basis for regarding
Lamarckism as a theory of hierarchy lies in this division. Lamarck, as we shall see,
always presents the two sets as separate in his later evolutionary writing, and
scholars of Lamarckism have accepted this contrast as crucial (Burkhardt, 1977;
Mayr, 1972; Simpson, 1961). But Lamarck, as noted several times above, remains
a frustrating figure for historians. His assertions are bold, even dogmatic; but his
arguments tend to be sketchy, full of elisions, or even self-contradictory. These
frustrations become most apparent in Lamarck's treatment of his two primary
forces (as Corsi, 1988, has discussed with great insight). The explicit assertions of
his later works rank the two forces as distinct and opposed, but both the ontogeny
and logic of