Theory of autopoiesis

The notion of boundary is, in fact, one central concept in the theory of autopoiesis. Inside the boundary of a cell, many reactions and correspondingly many chemical transformations occur. However, despite all these chemical processes, the cell always maintains its own identity during its homeostasis period. This is because the cell (under steady-state conditions and/or homeostasis) regenerates within its own boundary all those chemicals that are being destroyed or transformed, ATP, glucose, amino acids, proteins, etc. 

The absence of the emphasis on DNA, self-reproduction, and evolution in the theory of autopoiesis was certainly a reason for its lukewarm reception in the community of molecular biology - a difficulty that might have been avoided, had its authors been less rigid about the matter. In fact, it is not difficult to incorporate nucleic acids and enzymes into the autopoietic scheme. This was proposed more recently (Luisi, 1993 1997) and the corresponding modification is formally rather simple, as Figure 8.4 shows. 

It is important to clarify these questions they are not entirely clear in the primary literature. To this end, the notion of cognition in the theory of autopoiesis first needs to be clarified. The question of the relation between autopoiesis and life will be discussed under Necessary and Sufficient ... 

It was said earlier that the interaction with the environment, according to the theory of autopoiesis, must be implemented on the basis of the internal logic of the living. In other words, the consequence of the interaction between an autopoietic unit and a given molecule X is not primarily dictated by the properties of the molecule X, but by the way in which this molecule is seen by the living organism. 

The theory of autopoiesis is based on the observation of the actual behavior of a living cell. As such, it is not an abstract theoretical model for life - there are many of these - but a deductive analysis of life as it is on Earth. It is in a way a picture of the blue-print of cellular life, and it is fascinating to see how many concepts related to the process of life - emergence, homeostasis, biological autonomy, interactions with the environment, cognition, evolutionary drift, etc. - pour forth from this analysis in a coherent way. 

It is important here to emphasize that the theory of autopoiesis, in addition to offering a clear distinction between the living and the nonliving, permits one to conceive experimental systems which respond to the definition of minimal life. Since those systems must be provided with a physical, semipermeable boundary, micelles and vesicles immediately come to mind. This is the gist of some of the work carried out in our group in Zurich under the headline of chemical autopoi-esis , " ° which started from a collaboration with F. Varela. ... 

In fact, the life of a cell is the starting point for the development of the ideas of autopoiesis (from the Greek auto, or self, and poiesis, or producing) developed by Maturana and Varela (Varela et ah, 1974 Maturana and Varela, 1980 Maturana and Varela, 1998). The aim of this chapter is to review the notion of autopoiesis and to present it in the context of present-day research in the life sciences. This will imply some addition to, and modification of, the original theory and also of a recent review of mine on which the first part of this outline is based (Luisi, 2003b). 

Still, it cannot be said that the notion of autopoiesis is now familiar in mainstream science. The reason for this will be discussed later on, but it can be anticipated that this is partly due to the fact that autopoiesis theory is not centered on DNA, RNA, and... 

We go back now to basic autopoiesis, in order to consider what came as an interesting, and unexpected, development of this theory. By unexpected, I mean that even the authors of the Santiago school had not foreseen it. This is social autopoiesis. The main feature of autopoiesis is self-maintenance due to a process of self-generation from within. Although this concept came from the analysis of a living cell, it can be metaphorically applied to social systems. 

One advantage of the idea of autopoiesis is its extreme simplicity. This comes at the cost of a lack of structural and mechanistic details. Ganti s chemoton provides a more detailed and more complex view of the unit of cellular life (Ganti, 1975 2003). Let s now sketch the basic theory of the chemoton in order to draw a comparison with autopoiesis. 

There are some signs in the modern life sciences literature to indicate a return to a system theory of life processes, which emphasize collective, integrating properties -such as self-organization and emergence. In this new - perhaps more philosophically - mature Zeitgeist, autopoiesis could re-emerge as a very useful conceptual framework. 

From all the above, it is apparent that autopoiesis belongs epistemologically to systems theory, according to which it is the organization of the components that characterizes the quality of the system. Thus, the life of a cell is a global property, and cannot be ascribed to any single component. 

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