The Life & Mind Seminar Network

Autopoiesis and the System Boundary

Posted in General by N. Virgo on August 8, 2008

by Nathaniel Virgo.

Hi everyone

I would like to ask this community a question which I think is quite central to a lot of discussions that are taking place at the moment. It has to do with the role of an organism’s physical boundary in the autopoietic theory. I think a lot of tension arises from differing assumptions about this issue and I would like to draw people’s attention to some key parts of the primary literature which support a view that, I think, differs from many more recent interpretations.

I hope that this can contribute to the current ongoing discussion about the relationship between Developmental Systems Theory and autopoiesis. It’s also relevant to some discussions that took place at ALife XI this week, including Mike Wheeler’s talk on whether autopoiesis and the idea of extended cognition are compatible, and the debate about whether the model I presented can be a model of autopoiesis if the spots’ boundaries are blurred rather than distinct.

In Autopoiesis: The Organization of The Living (1972), Maturana and Varela introduce us to the concept of homeostatic machines. These are defined as “machines which maintain constant, or within a limited range of values, some of their variables,” a definition which will be familiar to most of us. However this definition is followed by an important clarification which seems to me to be fundamental to how the rest of the theory is to be interpreted. Since the clarification of this definition is so important I will quote the whole paragraph:

There are machines which maintain constant, or within a limited range of values, some of their variables. The way this is expressed in the organization of these machines must be such as to define the process as occurring completely within the boundaries of the machine which the very same organization specifies. Such machines are homeostatic machines and all feedback is internal to them. If one says that there is a machine M, in which there is a feedback loop through the environment so that the effects of its output affect its input, one is in fact talking about a larger machine M’ which includes the environment and the feedback loop in its defining organization. (section 1.2.a)

Thus if we wish to see a thermostat as a homeostatic machine that regulates the temperature of a room, it is not correct (in to the autopoietic language) to think of the thermostat as being the box on the wall that is connected to a heater and contains a thermocouple, because this machine (machine M) has a feedback loop that runs through the environment. When the temperature drops the thermocouple breaks a connection, which causes the heater (which is in the environment) to be switched off, causing the temperature to drop again. Since the thermostat relies on this feedback loop for its operation, we should actually define the thermostat as a larger machine (machine M’) which includes the heater, the air in the room, and the feedback loop that passes through them.

Why is this so important? The above quoted paragraph is positioned directly before the definition of an autopoietic machine is spelled out [see footnote 1], and just below that we are given the following key statement:

Therefore, an autopoietic machine is an homeostatic (or rather relationstatic) system which has its own organization (defining network of relations) as the fundamental variable which it maintains constant. [see footnote 2]

Autopoietic systems, then, are to be seen as homeostatic machines. It follows that their definition must be expanded in the same way if they rely on a feedback loop that runs through their environment. The implications of this cannot be overstated.

Let us take the excellent example that Mike Wheeler gave in his talk of an earthworm. Earthworms build tunnels, using sticky secretions to hold them open. I can’t find a reference for this right now but I think these secretions help to digest the soil, so that they move back and forth along the tunnels digesting their food again and again. In any case, earthworms have behaviours that modify their environment, and they rely on the effects of these behaviours to maintain their organisation.

So let us try to see an earthworm as a homeostatic machine whose fundamental variable is its own organisation. First let us take the boundary of this machine as being the physical boundary defined by the worm’s skin. There are many feedback loops within this boundary that contribute to this homeostasis. But the worm also builds tunnels using its secretions and then later uses those tunnels to travel along and find food. This is a feedback loop which runs through the environment, and we have been told what to do in this situation: our previous definition of the worm (system W, defined as being bounded by the worm’s skin) must be expanded to a larger system (system W’) which includes the tunnel, the secretions and the feedback loop that runs through them.

The following conclusion seems inescapable: in Maturana and Varela’s framework the network of processes that define the worm as an autopoietic system is not coextensive with the boundary of the worm-as-a-physical-object, it is much bigger. This will be the case with most if not all organisms. As soon as an organism’s homeostasis of organisation relies on a sensorimotor loop there will be feedback loops that run through the environment, and those parts of the environment will have to be included in the autopoietic system. Although the worm does have a physical boundary, and this is important in its definition, it is only the boundary of the worm-as-a-physical-object. It not the boundary of the autopoietic-system-that-defines-the-worm, because the boundaries of that system are much wider.

When I first started reading about the autopoietic theory there were many statements that seemed very strange to me, but with this interpretation they seem much less so: it is not strange to say that changes in an autopoietic system can only be caused by things internal to that system, because the system is defined to include all the relevant causal relations, whether they be within the physical boundaries or not. It is not strange to say that autopoietic systems have no inputs or outputs for the same reason: what we usually think of as inputs to a sense organ or outputs from a muscle are actually internal to the system, because the system is defined to include a large proportion of what we usually think of as the environment.

It’s worth noting that with this interpretation the autopoietic theory starts to look a lot more like the approach of Developmental Systems Theory: it’s about including all the relevant parts of the environment in the causal story that we tell about the organism.

There is one slight problem with this approach, which came up in the discussion at EPIROB about Developmental Systems Theory, and that is the problem of when to stop. It seems like there might always be a system external to the system through which an important feedback loop might run. Should the autopoietic system that defines a single worm include all the plants on Earth, which re-cycle its respired carbon dioxide back into oxygen, a process which it ultimately relies on to maintain its organisation? It seems to me that it might sometimes be useful to say that, and other times not. I believe that this problem is not insurmountable.

However, it seems to me that in many modern interpretations of autopoiesis, and perhaps even in later texts by Maturana and Varela, that this definition of an autopoietic system as extending beyond the physical boundaries of an organism is not present. Later versions of the official definition introduce a physical membrane, and one gets the impression that this membrane is supposed to define the boundary not just of the unity that the system constitutes, but of the system itself. The assumption seems to be that the autopoietic system that defines an organism is a network of processes bounded by the physical boundary of the organism that maintains its own organisation.

The trouble is that I find it hard to understand a lot of the autopoietic theory when interpreted this way. If we try to re-construct the story of the worm it seems quite problematic. It is now defined by a network of processes whose boundary is the physical boundary of the worm-as-a-physical-object. It can perturb its environment by leaving sticky secretions, and it can later come back and be perturbed by the presence of a tunnel, but it’s hard to find the language to express the causal relationship between these two things, because we’re told that there cannot be causal relations between things inside the system and things outside it.

So the question is, what do you think? I’m interested to know whether current researchers read Maturana and Varela the same way I do, as saying that autopoietic systems extend beyond the physical boundaries of the organisms they define. I think that resolving this question of the role of the organism’s physical boundary is important to a lot of current debates, and it would be really good to hear a few opinions on the issue.

[footnote 1] the full definition given in this text is as follows. Note that this version of the definition hinges on the constitution of a concrete unity in space but does not specify that this unity must be bounded by a distinct membrane.

An autopoietic machine is a machine organized (defined as a unity) as a network of processes of production (transformation and destruction) of components that produces the components which: (i) through their interactions and transformations continuously regenerate and realize the network of processes (relations) that produced them; and (ii) constitute it (the machine) as a concrete unity in the space in which they (the components) exist by specifying the topological domain of its realization as such a network.

[footnote 2] as I understand it, Ezequiel’s position is that this does not directly follow from the definition but requires a concept of adaptivity to be introduced as well; in that case I will assume that we’re talking about autopoiesis plus adaptivity rather than bare autopoiesis, since my point is about the interpretation of autopoietic systems as homeostatic machines.

For what it’s worth my personal feeling is that this quoted statement puts across the underlying idea of autopoiesis far more clearly and concisely than any of the attempted formal definitions that Maturana and Varela have given us; and that one does not lose much, if anything, by taking homeostasis-of-organisation as the defining feature of autopoiesis rather than a consequence of it.

2 Responses

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  1. ezequieldipaolo said, on August 12, 2008 at 10:56 pm

    I think this is a very good analysis by Nathaniel. However, I would be careful not to put much weight on these paragraphs. There are several problems (or at least ambiguities) in interpreting what M&V mean by a “machine” in this context and a homeostatic machine that conserves its own organization. I take these terms as markers of the intuitions guiding their writing.

    To begin with, the text in Spanish is slightly different.

    “Entre las maquinas, las hay que mantienen algunas de sus variables constantes o dentro de un rango limitado de valores. En la organizacion de esas maquinas, esto debe expresarse de tal modo que el proceso se defina como verificado integramente dentro de los limites que la misma organizacion de la maquina especifica. Tales maquinas son homeostaticas… etc” (accents in the original)

    There are a couple of things I would like to draw attention to. First one is the use of the term “limite” which is translated as “boundary” in English. This term is a bit broader. It means the point at which we cross a distinction. Notice also that it says “dentro de los limites que la misma organizacion de la maquina especifica”.

    The part is translated in the English version as

    “within the boundaries of the machine which the very same organization specifies.”

    This has a very different connotation from the original!!

    A more accurate translation would be:

    “within the limits specified by the very organization of the machine”

    The use of the phrase “boundaries of the machine” unavoidably brings all the wrong images. That 1) you have a machine as a physical object that is bounded and 2) that these boundaries are the machine’s own. The Spanish version is a bit softer and admits the following interpretation. It is the machine’s organization that specifies the limits. This is not the same as the organization (in the English vesrion) specifying the machine whose boundaries are being referred to.

    I don’t want to make too much of this. But only to notice that any notion of boundaries and limits remains an organizational notion. A thermostat, defined by physical boundaries (a plastic enclosure on the wall) is not a homeostatic machine. But a cycle of regulation involving what goes on in that box, the heater, the room temperature, etc, is a homeostatic machine (the whole of it is defined as homeostatic because a variable is regulated by the totality of this organization).

    It is in this (maybe trivial) sense that we should understand the statement that all regulation happens inside the machine (read “organized system of relations between processes that sustain the regulation”). [Here we should notice that this organization, however, is not itself sustained by the regulation therefore the system is not operationally closed, and that this leads to criticisms of causal spread.]

    But it is in this (broader sense) that I suggest we should understand the notion of the boundary of a living system, as an organizational notion. It so happens that too much is made (in this book and in other places) of the importance of the physical boundary. This emphasis may have been damaging.

    However, even as an organizational notion, there is indeed a boundary to living organisms. It is precisely the point of using organization to define a system. That you should be able to say whether something is or isn’t that system.

    If you follow a molecule as it crosses the membrane of a cell, from an organizational point of view, it makes little sense to ask whether the molecule is inside or outside the organism. All that matters, for this point of view, is whether the molecule is implicated in processes that sustain the closure of the autopoietic organization or not (ie whether it is irrelevant or damaging). What creates confusion is to think of the physical membrane as the *organizational* boundary. The physical membrane IS important because it contributes to the integration of the system as a system of molecular interactions. But it is NOT the boundary that separates the organism from its medium. That’s the organizational one.

    I must emphasize that to say this is not the same as to say that the network of causal relations that condition the possibility of the autopoietic system must be part of the autopoietic system (I remove the qualification “relevant causal relations” because I wouldn’t know how you would distinguish their relevance in purely causal terms). This is precisely where the notion of closure plays it role. A closed organization is one where processes relate to each other as a network of enabling conditions. This network closes on itself so that each process (or component) is at the same time dependent on others and an enabling condition for others to exist. There are other enabling conditions that allow these processes to exist. Of course! Energy and matter gradients, etc. But they do not form part of the organism because they are not sustained by the processes of constitution of the organism.

    (But surely the organism sustain some “external” processes that contribute to its own maintenance! Yes indeed. Niche construction, multiple epigenetic loops, etc. The organization of a closed system does not preclude the inclusion of such a system in other closed networks or their “intersection”. M&V say this themselves when they speak of the closure of the nervous system. It is however a bit of an undeveloped area that deserves more attention: what is the relation between embedded or “intersecting” closed organizations? (Intersection is not the right word, but cannot think of another one right now). In a multicellular system, should we or should we not count parasites as part of it? My guess is yes. But M&V run into ambiguities when they attempted to develop in this direction.)

    Sorry, not sure this clarifies much!


  2. nick said, on August 24, 2008 at 5:28 am

    physical boundaries play the role of enabling organisational boundaries. the question to ask is not ‘what does this boundary contain’, but ‘what does this boundary enable’?. when we seek to find the boundaries or ‘origin’ of a system witnin some pysical or organisational spaces, we are engaged in a cartesian search and as such we will find only homuncular anwsers. when we look inside and between boundaries, we will find space. matter tends to boundaries, which is why they exist in the places that they do.

    the intersting thing is that the creation of physical boundaries enables the development of organisational boundaries. when a metacellular or metamolecular system forms a physical boundary, this enables a new level of organisation. there is no reason to assume that the organisational processes enabled should occur on one side OR the other of this boundary. there are many reasons to make a working assumption that new processes enabled by the boundary will be discernible in the region close to the new boundary, but there is no reason to assume that they should be on this side or that.

    the attampt to ‘locate’ a system ‘within’ a boundary seems as cartesian as the attempt to locate mind within brain. new levels of systematic activity are enabed by the formation of new boundaries that bind together processes of the sytem into a new unity. we see this in a membrane that keeps all the bits of a cell in the same bit of space, or in the skin that keeps all the bits of our bodies in the same place.

    things are made of the ongoing construction of mutually supportive boundaries. the boundaries are the interesting bits, not the things they are imagined to ‘contain’, which are invariably anthropomorphic projections.

    the problem of relativity runs through all these discussions, and this doesn’t seem necessary, because we have a general theory of relativity. this tells us that the energy level of any particle or region of space is relative to the strongest local (and the rest, but they’re small) gravitational field. At any level of description, we will find that the strongest local gravitational field is, in terms of the relative directional force, some boundary of an appropriate neutral buoyancy density spectrum with respect to whatever force, entity and media we happen to be talking about. That is to say, a boundary between media. Is there another type of boundary? If so, what is it?

    the implication is that, at any level of description, it is the boundary about which a process exists that is the point of relativity. we see this when we need to form boundaries to have a talk about something.

    in summary, we should be looking at and around the boundaries, rather than in between them, in order to understand their role. other wise we will see only space, about which we may argue forever.


    if we want to understand boundaries, we need to look at the boundaries themselves, and at what is going on around them, on both ‘sides’, in terms of the processes the establishment of a boundary enables, rather than in term of the observational entity it is inferred to contain.

    we should not be afraid to step back and investigate the consequences of embodying and situating autopoietic theory within the world it aims to describe, because this will provide useful constraints and heuristics in the development of theory.

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