Biology Reference
In-Depth Information
becoming one of a diverse variety of particular molecules (water,
carbon disulphide etc.). In the same way, universal types of Cells
and Organisms differentiate into numerous individual identities:
muscle, bone or blood cells, rabbits, carrots, foxes etc.
Both these conceptions are ontologies of order from order. They
only differ in the origin of that order and its mode of production.
For holism, order comes from the whole that is imposed on the
parts: it is 'order from above' which reflects the “natural plan of
emergent evolution” of which Morgan speaks (EE p. 3). For genetic
determinism it is the reverse, order coming from the molecules that
form the organism: this is 'order from below' which gives substance
to the genetic information. In both theories however, order is
always at the origin of order.
This vision of a world organised into superimposed levels where
each thing has a specific place is nowadays hegemonic and seems
absolutely obvious to us. Nevertheless, the philosopher Jaegwon
Kim, who calls it the 'layered model of the world', has analysed it
in detail, and thus revealed its fragility (Kim, 2002). Even though
a great many researchers agree on it in principle, there are just as
many variants of this model which do not acknowledge exactly the
same levels. The differences between them, related to the historical
context and the discipline in which they have been produced, raise
the question of the objectivity of the layered model. Indeed, if it
really exists, there must only be one, in which each level is gener-
ated from the preceding level and where each thing must be able to
be placed in a unique position. The different variants would then
be only approximations. Now, Kim shows that if we go into detail,
the ideal is far from being realised. On the one hand, reality is often
arborescent rather than layered. Animals are not superior to plants,
as Morgan supposes, even though they manifest properties related
to their having a nervous system. They are two separate evolution-
ary branches. Some classifications recognise a human level above
that of animals, related to their having a mind or conscience. Others,
such as that of the reductionist philosophers Paul Oppenheim
(1885-1977) and Hilary Putnam, go directly from multicellular living
beings to social groups. These two classifications are not compatible
