Biology Reference
In-Depth Information
1.
INTRODUCTION
Living systems appear as highly complex integrated units formed out of many
different and complex chemical aggregates. Nothing similar in degree of com-
plexity exists in the inorganic world, neither among human-made artifacts, where
systems lack the deep integration and autonomy characteristic of living organ-
isms. This organization is an intricate web of chemical reactions organized
spatiotemporally. Organisms share the property that the functional molecules
of their material make-up (DNA, proteins, fatty acids, etc.) are fabricated by
internal processes. One could say that the functional hardware of living systems
is continuously changing as new proteins are constructed and other molecules
synthesized. The first conclusion, then, is that those components that make up
the system as a whole are, in their turn, generated through the web of interac-
tions of the whole system (in the sense that each process depends on several
others within the system). This apparent causal circularity - along with the deep
integration and high complexity of their components - makes the understanding
of biological systems extremely difficult. Thus, the explanation of biological
systems requires many different principles: physical and chemical laws, self-
organization, and even informational constraints.
Already, certainphilosophers acknowledged theproblemof deep integrationand
holism, which are so characteristic of biological systems. More than 200 years ago,
I. Kant (1790:1987) remarked that living systems are beings that organize them-
selves; they are systems whose parts depend on each other so that, taken as a whole,
a living being is both the cause and effect of itself. Scientists, however, have begun
to see living organisms froma holistic perspective onlymore recently.
1
In the 1950s
Rashevsky (1954) defended the idea that living organization can only be explained
in relational terms, i.e., every component in a biological organism will have an
explanation in which the other components of the system are involved. R. Rosen,
a disciple of Rashevsky, has held a similar view, defining organisms as 'systems
closed under efficient causation' (1991). In contrast to anyman-mademachine, liv-
ingorganisms are self-mademachines, in the sense that all the complex components
aremade within the system. In other words, the complex organization of living sys-
tems is a consequence of itself. To consider thewhole network as a result of a former
(lower) level made up of simpler isolable components whose properties determine
their interactions would be partial, and ultimately, useless. The reason is that many
of these components can only exist as such, as a consequence of the recursivemain-
tenance of the whole network. In other words, complex components depend on the
whole system.
1
With the important exception of Developmental Biology at the end of nineteenth century and the beginning
of the twentieth century.
