This paper provides 1) a description of what has historically become the traditional model for perception theory and the theory of knowledge, 2) a characterization of the assumptions underlying that model, and 3) a comparison of that traditional model to each of two recent models. The two recent models are the “information‐based” model of perception by the psychologist James J. Gibson, and the autopoietic or “organizational closure” model of perception by the biologists Humberto Maturana and Francisco Varela. A description of each model is presented, as are its underlying assumptions and conceptual viewpoint. The author’s intent, in an examination of the two recent models, is to show 1) that problems attendant to the traditional model, and to Gibson’s model as a variant of it, result from definitions within the ocular metaphor which describes that model; 2) that once the metaphor is discarded, both the theory of perception and the theory of knowledge can be differently circumscribed altogether; and 3) that the autopoietic model of Maturana and Varela has done just that.

The concept of autopoiesis, amended as a system theory, is necessary and sufficient to provide an operational definition of life, a set of criteria by which the living are categorically distinguished from the non-living. Limitations are placed on the domains in which autopoiesis may be exhibited.

Key words: Autopoiesis, physical domain, physical realization of autopoiesis, system logic of the living

Zelený and Hufford apply the criteria of autopoiesis 1) to Leduc’s osmotic systems to claim that certain non-biological physical systems are autopoietic, and 2) to ‘the human family’ to claim that spontaneous social systems are autopoietic. I find, first, that the authors fail to show either kind of system to be autopoietic, and further, that their claimed success at showing autopoiesis derives from fundamental problems of logical types: in confusing system levels (discrete system components as distinct from the unitary whole) and in conflating system domains (physical, biological, and social). Finally, I contend that by its criteria autopoiesis is restricted to systems in the physical domain – that is, components, transformations, and production in autopoiesis are necessarily physical. While spontaneous systems in the social domain may be marked by relationships among its members (and may even be organizationally closed), they are not autopoietic.

Key words: Autonomy, autopoiesis, autopoietic criteria, living systems, osmotic systems, social systems. spontaneous social systems, system domains, system levels

There are several deep and age-old questions which underly science, philosophy, psychology, and social theory: What is the nature of the world? What is the nature of life? and, What is the nature of human beings in the world? These are fundamentally questions of ontology,{1} that is, What sorts of things ‘are’ in the world? Equally ancient are the philosophical questions of ontogenesis, of how things ‘come to be’: What is the origin of the world? What is the origin of _the _living as one particular sort of thing in that world? and, What is the origin of society or social ordering among the living? And arising from these ontological questions is the fundamental question of epistemology: How do we, as human social beings, come to know the world in which we find ourselves? Both kinds of questions are evolutionary, that is, they are concerned not only with the nature of things in the world but how they come into being and how they change over time as well. These foundational problems – of what things are in the natural world, how they come to be, how they evolve, and how we can know them – are all major issues in contemporary science. They are brought to the fore in the focal paper of this special forum issue, and an international group of experts from several different fields has been chosen to shed light on them in the ensuing forum discussion.

“Autopoiesis” is the explanatory principle for the organization of living systems, a concept directly applicable to the problematic issues surrounding the origins of life. Because it provides criteria by which a system may be judged as living, autopoiesis can be used to characterize a minimal living system. Once these defining characteristics have been established, we can extrapolate the conditions which would have made possible the emergence of earliest life. Because autopoiesis is a principle of organization, it provides a definition of living systems not restricted to specific mole-cules or structures – that is, to those nucleic-acid/protein/lipid cellular life forms with which we are familiar. Autopoiesis provides the conceptual and systematic framework within which any living system may be identified. In examining living systems, then, autopoiesis gives us a literally “meta-physical” view of life.