Biology Reference
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each other, in contrast with a machine in which components exist only for each
other but cannot make each other:
In such a product of nature
every part not only exists by means of the other parts
,
but is thought as existing for the sake of the others and the whole, that is as an
(organic) instrument. Thus, however, it might be an artificial instrument, and so
might be represented only as a purpose that is possible in general; but also
its
parts are all organs reciprocally producing each other
. This can never be the case
with artificial instruments, but only with nature which supplies all the material for
instruments (even for those of art). Only a product of such a kind can be called a
natural purpose, and this because it is an organised and self-organising being [my
italics].
(Kant, 1914, ยง65)
The philosopher of science George Kampis (1991, p. 345) recently put it this way:
In a component system [a type of system defined by Kampis which includes
living organisms], due to the continual turnover that gives rise to the components
and then removes them from the system, no component and no higher structure,
organised form of the components, can persist, unless produced and renewed over
and over again.
I shall take this view of the cell as the foundation on which systems biology
must be built. For this to be possible, we must have a formal, abstract language
with which to describe the functional organisations that would make autonomous
self-fabrication possible. To my knowledge, only two such formalisations have
been developed. In the late 1950s, more than a decade before Maturana and
Varela invented the term autopoiesis, the theoretical biologist Robert Rosen put
forward a formalised treatment in terms of category theory of what he called
metabolism-repair or (M, R)-systems, which become self-fabricating when sup-
plemented with a mechanism that he called 'replication' (an unfortunate choice,
as it turns out, because it does not agree with modern biology's use of the term)
(Rosen, 1958a,b, 1959b 1972) (for a recent review and exploration of (M, R)-
systems see Rosen (1991); Letelier et al. (2006)). Later on he would summarise
the central property of such systems as being 'closed to efficient causation'
(Rosen, 1991). At the same time John von Neumann (1966) was developing
his theory of self-replicating automata which centred around the concept of a
universal constructor. In the rest of this chapter, I shall provide a rather informal
version of Rosen's formal language, and then use it to show how the main
tenets of these two theories can be merged and mapped onto cell biochemistry.
However, we first need to explore the central concept of autonomy, because it
goes hand in hand with the idea of self-fabrication.
