Between Boundaries: Defining Life in Autopoietic Theory and Plessner

Let us begin with the redeeming word of our age, the only thing “to be grasped on this side of all ideologies, on this side of God and the state, of nature and history; something from which ideologies may arise, but that with equal certainty also devours them again”: life (Plessner 2019, 1). What is it, how do we recognise it, and how does it work? We find ourselves in a world of things and objects, and strive to make sense of them. Based on their similarities, we group them into genera, and based on their differences, we look for the specific features which set them apart from their neighbours. Why do we do this, more or less explicitly? To survive, to sate our nagging curiosity, because we cannot help ourselves?

No matter the cause, one of the key differentiations we make is between living and non-living things. In other words, we try to distinguish what is alive. What is more, we seem to be pretty good at it, from early childhood on (cf. Leddon, Waxman, and Medin 2008). How do we manage this and using what criteria? In the answers of both Maturana and Varela (1987) and Plessner (2019), the notion of “boundaries” plays an important role, yet it figures on different levels of analysis.

In this essay, we shall try to show how their takes differ. Following an exploration of the very act of distinction and definition, we will first present the theory of autopoiesis, and then proceed with an exposition of Plessner’s transcendental-intuitive approach. In the final section, we will contrast the two views of boundaries and show the difficulties in marrying one to the other as well as what methodological lessons we may learn from them.

The Act of Distinction

One may be surprised to find that studying biology, although it is the study of bios, life, one pays the latter’s definition little attention. Perhaps it is because, as Plessner says, himself a zoologist and philosopher, “botanists and zoologists [are] simpler souls, people of intuition and not as sophisticated as physicists” and hence less drawn “to the hairsplitting of conceptual analysis if only because they work with solid objects whose status as real does not pose them any problems.” (Plessner 2019, xxi)

Indeed, Campbell Biology (Urry et al. 2017), a well-known textbook, does not even try, assuaging us that “the phenomenon we call life defies a simple, one-sentence definition.” (Urry et al. 2017, 3) Listing a series of features, from autoregulation to reproduction, they suggest that we “recognize life by what living things do.” (Urry et al. 2017, 3) The hairsplitting philosopher in us might flare up at this apparent cop-out, yet as we shall find, it is actually a solid point even if it may have been made for the wrong reasons.

Of course, in defining life, we cannot be satisfied with a mere “laundry list” of features. On the one hand, there is little agreement on how long this list should be, and what items it must include. On the other, many of the features sometimes touted as the hallmarks of life are either too narrow or too broad. Take autonomy for example: certainly the living organism displays a high degree of autonomy, namely it is a system “composed of processes that generate and sustain that system as a unity and thereby also define an environment for the system.” (Thompson and Stapleton 2009, 24). But so too do societies and nervous systems (Thompson 2007; Varela 1981), and yet we do not think of these as living in quite the same way. We might instead think it is the ability to reproduce, to produce offspring. In that case, we will be hard-pressed to convince a mule it is not really alive.

Furthermore, we might wonder whether it is the components of a thing or the relations between its components that make it what it is.[1]As one reviewer pointed out, it is not entirely clear why is it Varela thinks this is an either-or matter. Why should a criterion of life not demand both a certain kind of components as well as … Continue reading Indeed, what makes a table a table, the fact that it is composed of wooden legs, boards, and nails, or the particular arrangement of these parts into a usable surface for eating and working?

Analogically, the question is whether it is the organic matter and the constituent processes which vitalise it, or the particular manner in which these parts and processes are related and intertwined. As Razeto-Barry (2012) points out, while organic molecules are the kind of molecules that living beings are composed of, we do not seem to consider a smudged paste of organic matter to be alive. As such “it seems reasonable to think that what lets us distinguish living beings as such is based more on the nature of the relations between their components than on the nature of the components themselves.” (Razeto-Barry 2012)

All of these considerations have to be taken into account when we are trying to indicate this thing, this unity we call a living being – when we are, in Maturana and Varela’s (1987) words, “making an act of distinction” (40). Using a certain criterion of distinction we seek to discern a particular figure from its background. We distinguish a unity, an entity, an object, a (living) being from the multitude of things it is surrounded with.

Our question, then, is what criterion of distinction to use. What characteristics should we take into account when we are trying to figure out if a unity belongs to a certain kind or class of things, namely, living beings? For Maturana and Varela (1987) what we are trying to determine is the organisation of things, “those relations that must be present in order for something to exist” (42) and “that must exist among the components of a system for it to be a member of a specific class” (47). The parts of a chair, to return to our example, must be organised in such a way that we may sit on it. Its components are of little importance; it can be made of wood, plastic, or metal.

Of course, it is much easier to pin down the organisation of a chair than a complex unity like a living being. But since this is a distinction we find ourselves making on a daily basis and one biologists hardly seem to struggle with as they work with living stuff, a criterion surely must exist. Maturana and Varela think the essence of the organisation of living beings is that “literally, they are continually self-producing” (ibid., 43).

Autopoiesis

This self-production is an expression of what Maturana and Varela call the autopoiesis of living beings, a Greek compound coined by Maturana that literally means “self-producing.” It is a concept the pair refined throughout a series of articles and books (see e.g., Maturana and Varela 1980, 1987; Varela 1981). Though it has had little effect in biology, perhaps due both to its subtlety as well as a certain ambiguity in its presentation, Razeto-Barry (2012) argues that – with some specification – it is still one of the few that approximates a unifying definition.

The autopoietic organisation is a dynamic network of recurring interactions and processes of chemical transformations known as the metabolism. Its distinguishing property is that the “metabolism produces components which make up the network of transformations that produced them.” (Maturana and Varela 1987, 44) To use Varela’s favourite image, it is like Escher’s drawing of a hand drawing a hand that is drawing the first hand (Varela 1984). To use another, it is a system that pulls itself up by its own bootstraps. There is in fact no difference between the product and the producer.

A crucial component that this network produces is a boundary in the form of a cellular membrane which delimits the system that produces it from its surroundings, at the same time as it is a part of this very system (Maturana and Varela 1987, 44). This autopoietic network or system separates itself from its environment using its own means, even as it enters into a relationship with the environment.

The living being is, of course, also an autonomous system, one that “can specify its own laws, what is proper to it.” (ibid., 48) An autonomous system is operationally closed. This means that it is a network of interacting components whose interactions (a) generate the very network that generated these interactions in the first place, and furthermore, (b) constitute this system as a particular unity through these interactions. In more precise terms:

An organizationally closed unity is defined as a composite unity by a network of interactions of components that (i) through their interactions recursively regenerate the network of interactions that produced them, and (ii) realize the network as a unity in the space in which the components exist by constituing and specifying the unity’s boundaries as a cleave from the background. (Varela 1981, 15)

Now, as we can surmise, the particular processes, the interactions in an autonomous, operationally-closed system like that, as well as the components among which these interactions occur, may take on a variety of forms. Furthermore, such systems must always specify their boundaries, with which they delimit the area and circumstances under which they can maintain their identity, i.e., remain what they are. For example, the nervous system too can be thought of as autonomous, its components being neurons, and its interactions the levels of activity enacted through synaptic coupling; yet it is not, again, a living being of its own.

Figure 1. The outer circle stands for the autopoietic cell, the inner circle stands for the nervous system of vertebrates which is another operationally closed network within organisms, whereas the arrows with the squiggly line represent the bi-directional interaction of the organism with its environment. (Maturana and Varela, 2005, 147)

What sets autopoietic autonomy apart is that its processes are the physicochemical, metabolic production of components, chief among them being the semi-permeable membrane, which at one point Varela calls the “topological boundary” (1981). Autopoiesis, in other words, is “an explication of the autonomy of the living.” (Varela 1981, 14) This, then, is our criterion of distinction as we go about figuring out what is alive.

Intuiting Life

With autopoiesis as our criterion of distinction, an interesting difficulty crops up. Namely, Varela, Maturana, and Uribe (1974) claim aliveness is something we recognise “implicitly” (187). But it is not clear just how we could implicitly recognise the particular features of autopoiesis. Cellular metabolism is not something we can observe with ordinary perception. Living beings are multicellular organisations of thousands of such self-producing cells, indiscernible to the bare eye.

Even if we agree that autopoiesis is an acceptable scientific criterion of the objective structure of life, it is not a structure immediately given to us, at least not to the degree that our “implicit” ability to recognise life would call for.[2]The Jonasian notion of “life recognising life” is, however, explored in later enactivism; see Villalobos and Ward (2016) for a critical review. Of course, a scientific description of a state of affairs need not accord with our everyday sense of things. It is, however, in a manner of speaking – and simplifying his rather peculiar method greatly (see Ebke 2014) –, the challenge Helmuth Plessner takes up in the Levels of Organic Life and the Human (2019 [1928]). He wants “to discover the conditions of possibility that must be fulfilled in order for a certain state of affairs to pertain in our experience.” (Plessner 2019, xxxi)

Plessner wants to see how something can appear as living to the faculty of intuition (ger. Anschauung). He means it neither in the naive nor the Bergsonian sense, but instead uses the term similarly to Kant, for whom it relates to a cognitive faculty that supplies the spatially and temporally structured immediate representations of sensory experience; in Plessner’s modified use, it is the faculty through which we have “access to the qualitative features of things.” (Hyatt and Honenberger 2019, x) It is the faculty employed by the biologist and the ethologist (Plessner 2019, xxxi). It may include the qualities of sensations, such as colours and sounds, but more importantly, it also receives that quality of vitality we are trying to understand.

Let us return to the world of as-yet uncategorised bodily things we found ourselves in initially. Regardless of their status as living, they all share the same basic phenomenal characteristics such as colour, shape or size. Some of the things seem to have this something extra, a surplus, indicated in their “construction, their behavior in a medium, a milieu, even in relation to a ‘world’” (Plessner 2019, xxxiv). This is their vitality, the property of life (Plessner 2019, 84–85). It “materially changes not only the appearance of the particular thing, but also formally its mode of appearance.” (Plessner 2019, 85) In other words, rather than only changing a particular appearance or side of a thing, the presence of this property essentially changes the entire manner in which it does the appearing.

Is it a property we merely add to an aggregate of all the features of a thing? Or is it more than just a summand in a sum, more like a gestalt, a whole that is made qualitatively different as we add a property? When a child fills in the contours of a drawing with crayons, the previous whole or gestalt does not only attain a new feature, but becomes another gestalt. In the same way a thing would become a living thing.

Yet intuitively it seems as though the vital property is not on quite the same level as others (Plessner 2019, 93), that instead “the preponderance of vitality (manifest already in intuitive appearance) [is] based on a mode of ordering that is beyond gestalt” (Plessner 2019, 93). By virtue of its vitality, a living thing is not just a gestalt, a mere unity, but a “wholeness beyond gestalt.” On the one hand, we cannot submit to a mechanicist reduction of living beings into mere functional unities of parts. But neither can we accept scientifically untenable, indeterminable forces like an Aristotelian or a Drieschian entelechy, a non-material inner factor driving the organism. So what is it that makes a thing appear, and relatedly, as Plessner wants to show, be, alive?

Aspects of Boundaries

To everyday sensory intuition, everything appears with a certain contour, a border (ger. Rand). It is the line where it makes contact with other things, with what it itself is not. The thing is contained within a contour which is a “a pure transition of the thing-body to the medium that surrounds it.” (Plessner 2019, 95) Now we may ask ourselves, whether or not the contour belongs to the thing? Is the contour something the thing has on its own or something we only ascribe to it as outside observers? As Grene (1966) answers, “a box simply is where it is and stops where it stops.” (256) Its border is not really a part of its essence. It does not belong to it because it is determined from the outside.

In contradistinction, living things have their boundaries (Grenze). They are no longer merely the neutral in-between transition point, but the very transition and transitioning itself, the area in which the living thing actively executes its passing over to the medium it is in and back to itself. The “boundary is placed over against the body and beyond it and at the same time directed into it.” (Grene 1966, 256) The boundary in this case belongs to the body. It is not just bounded; it bounds. Living things are, in other words, “boundary-realizing bodies” (Plessner 2019, 126)

Figure 2. Plessner’s diagram of two possible ways of conceiving a boundary: as (I) an empty in-between where the boundary belongs to neither the body (B) nor the medium (M), or alternatively, to both of them: or (II) where the boundary belongs to and stops with the body (Plessner 2019, 98).

There is more to the whole of the living thing, then, than its gestalt, even if it may, prima facie, present itself as nothing more. The “boundary contour does not exhaust the meaning of the boundary” (Plessner 2019, 95). It cannot capture the living thing’s unique “being itself and being from out of itself.” (Plessner 2019, 98)

with this kind of boundary structure is not simply divisible into inner and outer; it is, through its relation to its boundary, both directed out beyond the body that it is and back into it again. (Grene 1966, 257)

Such a boundary is not a meaningless empty transition, but “rather of its own accord fundamentally distinguishes between the formation it encloses [begrenzt] as such from the other as other.” (Plessner 2019, 97) The living body does not begin and end only where the medium it verges upon ends; it begins and ends on its own, independent of “that which exists outside it” (98). A thing bounded in this way relates between what it itself is and the medium, the other that it is not. It is mediating between the interiority of its own identity and the exteriority of its surroundings, between its living body and its environment. As Mul (2014) puts it, living beings “have a relationship to both sides of their constituting boundary, both to the inner and the outer side” (16). As such a body

Thus arises a dual aspectivity of inner and outer, which Plessner will – later in the Levels – establish as the root of the Cartesian dichotomy while sidestepping its ontologisation. This dual aspect is what determines the formal mode of appearing of the living thing, without changing its material appearance, without a necessary difference in phenomenal content (Plessner 2019, 98). This “intuitive antagonism of the mutually inconvertible outward and inward directions as a determination of the body’s appearance” is a property of the living body, one that can be “only viewed, but not measured, […] cannot be demonstrated (represented), but only intuited” (Plessner 2019, 120).

It is indicated in a certain plasticity of the living thing, its malleability, stretchability of the contours which are as delimiting as they are shiftable (Plessner 2019, 116). The more plastic a thing appears the more alive it seems. We can see it in the regular irregularity of the living thing, its rhythmicity, its indeterminacy.

More importantly and constitutively, we see it in the living being’s positionality. Between the two aspects mediated by its boundary, the living being goes inward and outward (Plessner 2019, 120). To employ Plessner’s manner of speaking, it posits itself out beyond and outside of itself, and at the same time, into and inside of itself. It is out beyond itself and over against itself at the same time as it is into itself. It mediates itself to itself as well as to the medium it veers upon. To put it plainly, the living being takes a position. The non-living body “is as far as it reaches. Its being ends where and when it ends. It stops short.” (Plessner 2019, 121) The living body, meanwhile, goes farther than it reaches; it is reaching, achieving a certain “ease in itself.” The body sets itself apart from itself and again brings itself into relation with itself. It is both outside of itself and within itself. It is not merely situated in time and space, but claims its natural place for itself (Plessner 2019, 123).

There is a reason Plessner employs the kind of dynamic, if convoluted language he employs: “characterizing positionality in static terms is […] difficult” for life, in its very essence, “is movement, cannot take place without movement,” and “can only be by becoming; process is the mode of its being.” (Plessner 2019, 123). All this is expressed in its positional character, which we receive – as many of the other qualities and categories of life – intuitively. It is the basis of how the organism appears not a thing, but a being (Plessner 2019, 123): a living being.

Figure 3. On this diagram, we see three possible relationships of the thing with its environment. M stands for medium, B for body. In the case of (I) the boundary is dotted because it is not real or absolute; it is just a spatiotemporal formation. In (II) a relationship between the living body and its medium emerges where the boundary appears as an absolute solid line. But in this case the organism seems to be closed off from the environment. (III) shows the third alternative with the medium and the organism in a relationship. To a certain degree, the boundary is self-annihilating itself, opening the organism up and sidestepping absolute oppositionality. (Plessner, 2019, 183).

From Boundaries to Boundaries

The comparisons between the two notions of life we have sketched out invite themselves. They seem to deal with the same phenomenon. Both conceive of life as a kind of independent, autonomous unity or system constituting itself through a dialectical, mediating separation from its surroundings. Each seems to trace these features to the particular organisation of living things. The notion of boundaries figures in both. But it is the treatment of the latter which can serve to illustrate some differences both in the method of how the two theories proceed, as well as nuances in the view of life which result from it.

Insofar as they are conceptualising a minimal definition of life, Maturana and Varela (1987) and Varela (1981) explicitly define the autopoietic boundary as a topological, biochemical boundary, namely the semi-permeable membrane of the cell. Meanwhile, for Plessner, this physical realisation of the boundary is of secondary importance in his analysis:

“The factors upon which the boundaries are based and that in physics and chemistry are defined as forces of cohesion, chemical bonding, and so forth, have to be left aside in the logical analysis of this state of affairs.” (Plessner 2019, xxxii)

Rather than focusing on the possible biochemical underpinnings of boundedness, he notes we should not seek to understand it “in any derived way, but in its visual and tactile intuitiveness.” (Plessner 2019, xxxii). Yet for Maturana and Varela, it is a physical structure, observable under a microscope. It can be outlined, its contour determined. It is a measurable quantity. Indeed, Varela and Goguen (1978) went to great lengths to mathematically specify the conditions of the operational closure necessary in an autonomous system, including living systems.

For Plessner, on the other hand, the boundary is primarily an intuitive quality; it “can only be understood, not drawn.” (Plessner 2019, xxxii) It is not something we could sense in the mere sensory appearance of a thing. These constitutive essential characteristics

as categories of life can only be fully grasped (individually and overall) by intuition. These characteristics define life; they never feign it. But they define life as being for intuition, having nothing directly to do with those layers of being conceptualized by physics and chemistry. (Plessner 2019, 107) […] It is true that this inevitably removes such a theory from the sphere of concrete sensory intuition in which the essential characteristics of life are embedded (without themselves being of a sensory nature). (Plessner 2019)

This does not mean that Plessner denies the boundary may have a physical realisation or correlate. In the appendix to the Levels, he summarises biochemical findings that draw the origin of life to the appearance of membranes which separated the multimolecular organic open system from its environment while simultaneously allowing their interaction (Plessner 2019, 331–33). The membrane stabilises the outline and thus gives the organism form, marking it as a particular living entity, an individual, both enclosing it and at the same time opening it to its setting, thereby facilitating its metabolism (Plessner 2019, 332).

“The effect of such structural cohesive forces on the surface,” he goes on, “is the decisive factor: they turn the outline into a boundary, in which two mutually affecting areas come to mediate each other without infringing upon the outlined body’s structure.” (Plessner 2019, 333) As such it is membranes that, “because they facilitate the stabilization of form,” lead to the emergence of the living whole beyond a gestalt, a whole which is self-sufficient and “uses its components as a means of self-preservation” (Plessner 2019, 333). In a mere appendix note, Plessner thus presages the autopoietic theory.

But on the other hand, we have seen, of course, that the topological boundary is not the only kind of boundary Varela (1981) deals with. Every autonomous system must specify a boundary for itself, within the bounds of which it can maintain its identity, or else, disintegrate. The topological boundary is just an explication of the formal autonomic boundary.

The differences arise because the theories proceed at different levels of analysis. Plessner begins with the phenomenon of life as it appears, indeed, with its unique mode of appearing. Consequently, he first sees the living whole, the organism, and then uses the boundary-realizing mode of appearance of this whole to define life and derive its constitutive features. Maturana and Varela, on the other hand, presuppose this intuitive level without delving into it and seek instead to analyse the implicitly intuited whole into its minimal basis, i.e., the autopoietic cell.

The difficulty lies in the fact that, in several places, they use precisely this minimal form of life for the (minimal) definition thereof. What this definition does not capture well is the nature of living things as they appear to us: as living wholes, not aggregates of cells. Their conception of autonomy approximates the whole organism better, yet in that case we must still determine what is it about the living autonomous system that differentiates it from every other kind of autonomous system. It remains unclear how exactly a living autonomous system might “inherit” the aliveness of the autopoietic cell, if its constituent cells – being dependent on one another to exist rather than independently self-productive – can even be called autopoetic.

Plessner’s reliance on intuition as the level of analysis at which he chiefly operates and from which he forms his deductions is an important feature of his system, though we do not have the space here to explore it in-depth. In fact, the entirety of his philosophy of life – and by extension, his philosophical anthropology – is derived from it (see Ebke 2014). We have seen that positionality and dual aspectivity, which both follow from boundedness, are also something we notice intuitively, as are all the other modals, or irreducible categories, of life, many of which are, in fact, inaccessible to sensory evidence. For mere experience

cannot be called upon as a deciding factor here. Every true experience reduces the content acquired purely by intuition to the criterion of observability. Observing or representing a state of affairs, however, means to grasp it in such a way as to make it given in more than one manner. Essential for representation, then, is the translatability of a state of affairs from one mode of givenness into another, or making it given in more than one sensory modality. (Plessner 2019, 111)

More Thought than One Thinks

In our brief exposition, our primary goal was to introduce the elements necessary to compare the notion of boundaries in both the autopoetic theory and the philosophy of life of Plessner. We have seen how the respective senses of boundaries figure on different levels of the analysis of life which indicate methodological divergences, even if they produce related results.

We have not explored the manifold directions in which these theories develop. Maturana and Varela (1987) use autopoiesis to explain the coupling of organisms with their environments and at the same time arrive at a unique, non-representationalist conception of cognition. Plessner (2019) develops the vital categories of life, by way of exploring the different forms of life or positionality, to arrive at an understanding of humans as excentric beings in a reflexive relation to themselves, allowing him to comprehend the human as a cultural, naturally-artificial creature. These are just some of the areas they delved into.

Figure 4. A portrait of Helmuth Plessner in 1972 by Thea Goldmann (source: samisdat-dejung.ch) and a drawing of Humberto R. Maturana (left) and Francisco J. Varela (right) (source: theclinic.cl).

Science, presenting itself as the objective, historically and culturally indifferent description of reality, often displays a marked ignorance of the history of thought. Beyond the obligatory mention of Galileo and a Schnellkurs of Kant, its perspective tends to be limited to its immediate antecedents while ignoring the vast majority of thinkers whose ideas it then proceeds to stubbornly rediscover. Every so often a new fashionable paradigm emerges which, under scrutiny and with some historical perspective, turns out to be little but a reinvention of the wheel, repeating all the mistakes of our ancestors.

To this end, the renaissances of forgotten thinkers who treaded the paths we are treading and their juxtapositions to modern theories are more than welcome as they help establish precisely this perspective. Enactivism has proven to be a fertile paradigm which can be usefully informed in combination with thinkers like Plessner and Merleau-Ponty. But we must also take care not to get ahead of ourselves, to avoid converting thoughts into each other which are not commensurate, picking up theories “like teenage girls read novels, eager to find out whether they’ll end up together.” (Plessner 2019, 27) We must pay greater attention to the architecture of these different thought systems and beware of an uncritical eclecticism.

“Hardly anyone bothers going to the trouble anymore of thinking about the framework in which a work is enclosed. This sloppy kind of reading is of course promoted by an approach to philosophizing that is no longer systematically schooled or, conversely, by the premature systematism of little world builders. Patience, empathy, and respect for the intentions of the other seem to be virtues of bygone times.” (Plessner 2019, 27)

Plessner, noting the similarities of his work to Merleau-Ponty, who published his works later, wonders whether the latter “had perhaps read the Levels after all.” But not all convergence is due to influence, and indeed, we might add, not all convergence is convergent. We can only agree with him when he says that “[t]here is more thought in the world than one thinks.” (Plessner 2019, xxxv)

References

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Grene, Marjorie. 1966. “Positionality in the Philosophy of Helmuth Plessner.” The Review of Metaphysics 20 (2): 250–77.

Hyatt, Millay, and Phillip Honenberger. 2019. “Translator’s Preface.” In Levels of Organic Life and the Human: An Introduction to Philosophical Anthropology. New York: Fordham University Press.

Leddon, Erin M., Sandra R. Waxman, and Douglas L. Medin. 2008. “Unmasking ‘Alive:’ Children’s Appreciation of a Concept Linking All Living Things.” Journal of Cognition and Development : Official Journal of the Cognitive Development Society 9 (4): 461–73. https://doi.org/10.1080/15248370802678463.

Maturana, Humberto R., and Francisco J. Varela. 1980. Autopoiesis and Cognition: The Realization of the Living. Boston Studies in the Philosophy of Science, v. 42. D. Reidel Publishing Company.

———. 1987. The Tree of Knowledge: The Biological Roots of Human Understanding. Shambhala Publications, Inc.

Mul, Jos de. 2014. “Artificial by Nature: An Introduction to Plessner’s Philosophical Anthropology.” In Plessner’s Philosophical Anthropology: Perspectives and Prospects. Amsterdam: Amsterdam University Press.

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Razeto-Barry, Pablo. 2012. “Autopoiesis 40 Years Later. A Review and a Reformulation.” Origins of Life and Evolution of the Biosphere : The Journal of the International Society for the Study of the Origin of Life 42 (October). https://doi.org/10.1007/s11084-012-9297-y.

Thompson, Evan. 2007. Mind in Life: Biology, Phenomenology, and the Sciences of Mind. Cambridge, Mass: Belknap Press of Harvard University Press.

Thompson, Evan, and Mog Stapleton. 2009. “Making Sense of Sense-Making: Reflections on Enactive and Extended Mind Theories.” Topoi 28 (1): 23–30. https://doi.org/10.1007/s11245-008-9043-2.

Urry, Lisa A., Michael L. Cain, Steven Alexander Wasserman, Peter V. Minorsky, Jane B. Reece, and Neil A. Campbell. 2017. Campbell Biology. Eleventh. New York, NY: Pearson Education, Inc.

Varela, F. G., H. R. Maturana, and R. Uribe. 1974. “Autopoiesis: The Organization of Living Systems, Its Characterization and a Model.” Biosystems 5 (4): 187–96. https://doi.org/10.1016/0303-2647(74)90031-8.

Varela, Francisco J. 1981. “Autonomy and Autopoiesis.” In Self-Organising Systems: An Interdisciplinary Approach, edited by G. Roth and H. Schwegler. Frankfurt: Campus Verlag.

———. 1984. “The Creative Circle: Sketches on the Natural History of Circularity.” In The Invented Reality, edited by Paul Watzlavick. New York: Norton Publishing.

Varela, Francisco J., and Joseph A. Goguen. 1978. “The Arithmetic of Closure.” Journal of Cybernetics 8 (3-4): 291–324. https://doi.org/10.1080/01969727808927587.

Varela, Francisco J., Evan Thompson, and Eleanor Rosch. 2016. The Embodied Mind: Cognitive Science and Human Experience. Rev. ed. Cambridge, MA: MIT Press.

Villalobos, Mario, and Dave Ward. 2016. “Lived Experience and Cognitive Science Reappraising Enactivism’s Jonasian Turn.” Constructivist Foundations 11 (2): 204–12.

References

1 As one reviewer pointed out, it is not entirely clear why is it Varela thinks this is an either-or matter. Why should a criterion of life not demand both a certain kind of components as well as specific relations?
2 The Jonasian notion of “life recognising life” is, however, explored in later enactivism; see Villalobos and Ward (2016) for a critical review.