This article intends to highlight the main features of the theory of autopoiesis by Humberto Maturana and Francisco Varela, two Chilean neuro-biologists who, in the early 70s, addressed the question “What is life?”, and connected it to the question “What is cognition?” Their answers, conveyed in a series of publications that started in 1973, can be seen as original developments of the innovative scientific approach to the description of life and cognition that arose between the 20s and the 70s, and that usually is ascribed to emerging research lines such as the sciences of systems, complexity and self-organization, and, more in detail, to scientists such as Ludwig von Bertalanffy, Norbert Wiener, Gregory Bateson, Heinz von Foerster, Paul Weiss, Ilya Prigogine, and Jean Piaget, among others.
This approach relies on a radical rejection of the classical reductionist method that requires scientists to study living systems by dissecting them in their components. The new methodological attitude is based on the insight that, in order to study life, science has to focus not on the individual components of living systems, but on their interactions, that is, on the networks of relations constituting them as wholes. The main idea is that, in living systems, the whole, as the organization of its parts, yields the property of life, while the single parts participate to life only because they are integrated in the whole.
This is the “systems view” of life, as described and discussed by Ludwig von Bertalanffy (1968), and more recently in Capra and Luisi's book (2014). A series of notions define and support this perspective. A very important one is the theoretical concept of emergence, or emergent property, that expresses the idea that the interconnection of a multiplicity of components in a system generates novel global properties: novel in the sense that cannot be found in, nor can be deduced from, the properties of the single components-for example life itself, which can be found not in the single components of a cell (lipid, nucleic acids, proteins, polysaccharides, etc.), but only in their network of interactions.
Another crucial notion is that of thermodynamically open system, which qualifies systems that need to receive energy and nutrients from the environment, otherwise they loose their organization – their individuality – and dissolve. Prigogine correlated this notion with the concept of dissipative structure, which designates systems, not only biologic, which maintain dynamic, ordered, structures although being far from equilibrium. Wiener introduced the idea of feedback loop to describe the way in which a system can maintain its material identity while interacting with an ever-changing environment. This notion ascribes to living systems a circular organization: a closed correlation of components in which every element induces an effect on the next one, and the last one acts on the first one. The idea is that of a circular causality allowing homeostasis as the result of biological self-regulation: the capability of living systems to react to external perturbations so to compensate the alteration and restore the standard global dynamics of the systems.
These notions are closely related to the concept of organizational closure, introduced to describe the formal structure of metabolism, that is, the basic organization of the living: a network of elemental operations of synthesis and destruction of components in which every operation triggers another one, and regenerate the living process of metabolic self-production. The concept of closure, which integrates that of feedback loop, is at the basis of the notion of biological autonomy. The latter designates the capability of living systems to determine their structure, their dynamics and their self-regulative behaviours by themselves, controlling from within their process of self-production. Taking the example of an already very complex living system, an ant does not need any information from the outside medium in order to be an ant. This set of notions opened the way to the introduction, by Maturana and Varela, of the theoretical concept of autopoiesis, which, given the limits of this short article, we will try to describe in a nutshell.
Maturana and Varela did not follow the conceptual lines described above, but implicitly incorporated them in a phenomenological approach to the biological cell. Figure 1 illustrates in a cartoon form the metabolism of a cell, with the very many chemical transformations. There is here apparent paradox: despite all these changes, the cell maintains its own individuality – a liver cell remains a liver cell, and amoeba remains an amoeba, and so on.
How is this possible? It is possible because the cell is capable of regenerating from within all the compounds which are being transformed – glucose, or ATP, proteins or nucleic acids… – at the expenses of nutrients and energy coming from the outside. The living cell, as all living organism, is a ‘factory’ – a system – that produces itself (auto-poiesis: self-production) from within, by producing its own components. As Maturana and Varela stated: “living systems transform inside themselves matter, in such a way that the product is their own organization”, and Maturana added: “When you regard a living system you always find a network of processes or molecules that interact in such a way as to produce the very network that produced them and that determine its boundary. Such a network I call autopoietic.”
There would be much to say in order to clearly describe the autopoietic view of life. To limit our description to the essentials, we would like to focus the attention on two different and complementary aspects of autopoietic systems: organization (their invariant dimension), and structure (their variant dimension). With the term ‘structure’ Maturana and Varela referred to the concrete materialization of living systems, which changes not only from one system to the other (for example there are different kinds of cells), but also in the same system at any step of the metabolic dynamics. At the same time, all cells, and all living organisms, are characterized by a common denominator: the invariant circular mechanism of metabolic autopoiesis, which Maturana and Varela defined as the universal ‘organization of the living’. According to them, all forms of life comply to this principle, so that autopoiesis can be understood as a universal principle of life. As such, it permits the three main forms of existence of the cell, as exemplified by the following illustration.
Note in particular, in fig.3, the agent A coming from the external medium. The interactions of the autopoietic system with the environment are crucial at both levels of the biological dynamics – ontogenesis and evolution. According to Maturana and Varela, what happens during these interactions strictly depends on the autopoietic structure. In line with this view, called structural determinism, an exogenous perturbation, such as an external agent, can trigger, but not determine a structural change in an autopoietic system. The autopoietic structure defines which, among all the external events, can be accepted as consistent with the internal organization, accepting then the consequences on the structure of the system. On this basis, the interaction between an autopoietic system and its medium is conceived by Maturana and Varela as a process of structural coupling: a symmetric relation of mutual perturbations and endogenous processes of self-regulation that generates a permanent dynamics of co-adaptation, or co-evolution. Within this coupling, the autopoietic system and the external medium co-define their dynamical configurations, not by direct action of one on the other, but by triggering in the other self-regulative behaviors. As Varela put it, at any instant of their interaction, the system and its medium ‘co-emerge’.
The self-regulative dynamics through which the autopoietic system maintains its coupling with the medium is conceptualized by Maturana and Varela in terms of “cognition”. This concept intends to emphasize that an autopoietic system is able to perceive external events as perturbations, and to react to them by adopting internal configurations of self-regulation by maintain its organization in the given environmental conditions. In other words, the autopoietic system is a system able to create, for the external pressures that it perceives, internal operational that allows it to maintain its individuality – to survive in its ever-changing medium. On this basis, the theory of autopoiesis describes all living organisms – including bacteria – as cognitive systems. A biological system lives because it knows how to operate in its medium in order to maintain its autopoiesis. Note that these operations ‘in its medium’ can only be described by an observer. For example: given an amoeba in a sugar gradient, the observer can say that the amoeba interacts with its environment in order to get nutrients. The amoeba does not ‘know’ anything about environment or nutrients – the amoeba simply compensate the perturbations it perceives and thus maintain its internal organization, working as an operationally closed system.
As Maturana put it, cognition is not a defining condition of life. Cognition is what the organism does. Cognition is the doing. Autopoiesis is the sufficient and necessary condition for life, and life, as such, implies cognition. This view of cognition has important epistemological consequences. One of the most relevant is that different autopoietic systems, endowed with different structures, perceive and react differently to the pressures of the medium. This means that, in the perspective of the Santiago’s school, there are as many cognitive worlds as many different living organisms. This form of cognitive pluralism implies the dissolution of the classical notion of objectivity, opening a new gnoseological space for cognitive biology: a space in which the authoritarian reference to ‘one objective external reality’ expresses not the Truth, but the incapability of recognizing and respecting the cognitive experience of the others.
Text by Pier Luigi Luisi (Prof. Emeritus ETHZurich, Switzerland) and Luisa Damiano (University of Messina, Italy)
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Damiano L. , Co-emergences in life and science, in Synthese, 185, pp. 273-294
Luisi P. L. , The Emergence of Life, 2nd edition, Cambridge University Press, 2016 (with a long conversation with H. Maturana on cognition)
F. Capra and P.L. Luisi, The systems view of life, Cambridge Univ. Press, 2014, italian edition Vita e natura. Una visione sistemica Aboca Museum
Maturana H. and Varela F. , De Máquinas y Seres Vivos, Editorial Universitaria, Santiago
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Maturana H. and Varela F. , El arbol del conoscimento, Editorial Universitaria, Santiago