Biology Reference
In-Depth Information
of evolution and variation, while genetics is a theory which privi-
leges the point of view of ontogenesis and the invariant form. For
this reason, synthesising the two theories was very difficult and did
not occur spontaneously. It only became possible in the middle of
the 20th century and its story has already occasioned in-depth
studies which highlight the difficulties encountered (Gayon, 1992A,
1992B). What is of particular interest to us here is the question of
the coherence between Darwinism and genetic determinism, and
from this point of view, the price paid for synthesis was very high.
To preserve a minimum of coherence, DNA has had to be attrib-
uted a role of omnipotent governor of biological processes which
brings into play very different mechanisms according to circum-
stances. It allows evolution, through its random mutations, on the
basis of a probabilistic mechanism, and also directs ontogenesis by
functioning as a deterministic programme (a Form) which elimi-
nates molecular chance.
We have seen the consequences of reintroducing an Aristotelian
conception. For DNA to be able to play its role as genetic infor-
mation, ontological separation between the physical/chemical and
biological processes has to be acknowledged. While the first are sub-
ject to a principle of order from disorder, the second are subject to
one of order from order. In addition, to give an effective content to
this principle of order from order, molecular biologists have been
obliged to postulate the stereospecificity of interactions between
biological molecules, from which arises the contradiction of genetic
determinism.
This persistence of hylemorphic ontology, despite the problems
that it raises, leads to a question. Does it express, as is generally
accepted, the relevance of this ontology for treating living organ-
isms, or is it not rather a symptom of our inability to formulate an
appropriate theory? Indeed, not only has hylemorphic ontology
repeatedly reappeared in the history of biology, whereas it was
abandoned in physics at the time of the Copernican revolution, but
it has also been maintained in the 20th century in the form of the
genetic theory, despite this theory having been contradicted from
the beginning by experimental data.
