Minimalism is a useful element in the constructivist arsenal against objectivism. By reducing actions and sensory feedback to a bare minimum, it becomes possible to obtain a complete description of the sensory-motor dynamics; and this in turn reveals that the object of perception does not pre-exist in itself, but is actually constituted during the process of observation. In this paper, this minimalist approach is deployed for the case of the recognition of “the Other.” It is shown that the perception of another intentional subject is based on properties that are intrinsic to the joint perceptual activity itself.

Key words: sensory-motor, dynamics, perception, minimalism

This article revisits the concept of autopoiesis and examines its relation to cognition and life. We present a mathematical model of a 3D tesselation automaton, considered as a minimal example of autopoiesis. This leads us to a thesis T1: “An autopoietic system can be described as a random dynamical system, which is defined only within its organized autopoietic domain.” We propose a modified definition of autopoiesis: “An autopoietic system is a network of processes that produces the components that reproduce the network, and that also regulates the boundary conditions necessary for its ongoing existence as a network.” We also propose a definition of cognition: “A system is cognitive if and only if sensory inputs serve to trigger actions in a specific way, so as to satisfy a viability constraint.” It follows from these definitions that the concepts of autopoiesis and cognition, although deeply related in their connection with the regulation of the boundary conditions of the system, are not immediately identical: a system can be autopoietic without being cognitive, and cognitive without being autopoietic. Finally, we propose a thesis T2: “A system that is both autopoietic and cognitive is a living system.”

Key words: Autopoiesis, cognition, life, tessela- tion automaton, random dynamical system, boundary conditions

The following basic question is studied here: In the relatively stable molecular environment of a vertebrate body, can a dynamic idiotypic immune network develop a natural tolerance to endogenous components? The approach is based on stability analyses and computer simulation using a model that takes into account the dynamics of two agents of the immune system, namely B-lymphocytes and antibodies. The study investigates the behavior of simple immune networks in interaction with an antigen whose concentration is held constant as a function of the symmetry properties of the connectivity matrix of the network. Current idiotypic network models typically become unstable in the presence of this type of antigen. It is shown that idiotypic networks of a particular connectivity show tolerance towards auto-antigen without the need for ad hoc mechanisms that prevent an immune response. These tolerant network structures are characterized by aperiodic behavior in the absence of auto-antigen. When coupled to an auto-antigen, the chaotic attractor degenerates into one of several periodic ones, and at least one of them is stable. The connectivity structure needed for this behavior allows the system to adopt particular dynamic concentration patterns which do not lead to an unbounded immune response. Possible implications for the understanding of autoimmune disease and its treatment are discussed.

In this paper we present a new model for the mechanism underlying what is traditionally known in immunology as the “selfnonself” distinction. It turns out that in operational terms, the distinction effected by this model of the immune system is between a sufficiently numerous set of antigens present from the start of the ontogeny of the system on the one hand, and isolated antigens first introduced after the system has reached maturity on the other. The coincidence between this “founder versus late” distinction and the traditional “somatic self-foreign pathogen” one is essentially contingent, an example of the purely opportunistic tinkering characteristic of biological organization in general. We conclude that the so-called “self-nonself” distinction in immunology is a misleading misnomer. This raises the question as to what would genuinely count as a “self-nonself” distinction, a fundamental question for biology in general and Artificial Life in particular.

Based upon the shape-space formalism, a model of an idiotypic network including both bound and free immunoglobulins is simulated. Our point of interest is the network development in the context of self antigens. The investigations are organized around simulations initiated by various spatial configurations of antigens; the behavior of the system with respect to antigens is analyzed in terms of morphogenetic processes occurring in the shape space. For certain values of the parameters, the network expands by traveling waves. The resulting spatial pattern is a partition of the shape space into zones where introduction of an antigen entails an infinite growth of the clones binding to it, and into zones where, on the contrary, the anti-antigen idiotypes decrease. Among the parameter combinations tested, some produce a partition that remains static whereas others produce a partition that changes in time. For other values of the parameters, the patterns generated do not partition shape space into zones; in these cases, it is observed that the system systematically explodes when an antigen is present.

The concept of autopoiesis was conceived by Maturana and Varela as providing the necessary and sufficient conditions for distinguishing the living from the non-living (and, by extension, the cognitive from the non-cognitive). More recently, however, there has been a growing consensus that their original conception of autopoiesis is necessary but insufficient for this task as it fails to meet a number of constructive, interactive, normative, and historical requirements. We argue that it also fails to satisfy crucial phenomenological requirements that are motivated by the ongoing appropriation of autopoiesis as a key concept in enactive cognitive science. The root of these problems can be traced to the abstract general systems framework in which the ideas were first formulated, as epitomized by Ashby’s cybernetics. While this abstract generality has helped the concept’s popularity in some circles, we insist that a restriction of autopoiesis to a radical embodiment in chemical self-production under far-from-equilibrium conditions is necessary if the concept is to live up to its original intentions.

We very much appreciate that Maturana (2011) responded to our article, where we had made an attempt to excavate some of the hidden conceptual context in which the idea of autopoiesis had originally been formulated (Froese & Stewart, 2010). Our investigation was motivated by the growing interest in autopoiesis and related ideas among a new generations of researchers in cognitive science, driven by the increasing popularity of the enactive approach to cognitive science (Stewart, Gapenne, & Di Paolo, 2010). This enactive paradigm has been developed as an alternative to the traditional cognitivist-computationalist paradigm, and it is remarkable for its serious consideration of first-person experience and biological autonomy, two important domains of human existence that have so far been neglected in cognitive science.

Key words: Maturana, representation, embodiment

A l“encontre de l“acception classique, qui voit dans la représentation le tenant-lieu d“un référent prédonné, nous proposons une définition de la représentation comme activité de rendre présent. Cette approche, qui s“origine dans le concept phénoménologique d“intentionnalité, ouvre les sciences cognitives à un programme de recherche fondé sur l”énaction et renvoie à une définition de la cognition ancrée dans le vivant. Or des dispositifs de couplage sensori-moteur médiatisent le co-avènement de l“organisme et de son monde propre. Inamovibles chez l“animal, ces dispositifs deviennent amovibles chez l“homme et donnent lieu à des prothèses techniques qui lui permettent une inventivité inédite. Anthropologiquement constitutive, la technique médiatise ainsi la représentation par une mémoire externe inscrite dans des objets matériels. Au plan phénoménologique, elle instaure une genèse technologique de l“intentionnalité qui ébranle le partage traditionnel entre l“empirique et le transcendantal.

Key words: phenomenology, intentionality, representation