Biology Reference
In-Depth Information
“
Thus all morphological development is contained in the previous
state. This work is pure repetition; it does not have its reason at
each instant in a force currently active; it has its reasons in an
anterior force. There is no morphology without predecessors.
In reality we do not witness the birth of a new being; we see
only a periodic continuation. The reason for this apparent creation
is therefore not in the present; it is in the past, at the beginning.
We cannot find it among the secondary or actual cause; it must be
sought in the primary cause.
The living being is like the planet that describes its elliptical
orbit in virtue of an initial impetus…”
(LPL pp. 240-241).
A little farther on, in one of his rare allusions to the question of
the species, Bernard adds:
“It is unnecessary to see in this tendency to return to the starting
point any particular mysterious force that watches over the con-
servation of the species. If things happen in this way it is because
the being is in some way imprisoned by a series of conditions which
it cannot escape, since they are always repeated in the same way
outside and inside it”
(LPL pp. 241-242).
The birth of modern evolutionary biology and of modern biol-
ogy of the organism is thus linked, in the 19th century, to an anti-
essentialist point of view which rejects the hylemorphic ontology.
As first principle, this point of view substitutes the idea of the
genealogical line or biological continuum for the notions of the indi-
vidual organism and the species based on the concept of Form.
Nevertheless, Form would very rapidly return with a vengeance
with the advent of genetics.
7.4
The return of Form
Quite a few researchers have contributed to the rapid development
of genetics, but Weismann occupies a dominant position. He intro-
duced fundamental concepts which marked a radical break with the
pangenetic theory. As Aristotle had done with Hippocrates' theory,
