The notions of collective autocatalysis and of autopoiesis are clear¬ly related; equally clearly, they are not quite the same. The purpose of this paper is to try to clarify the relationship. Specifically I suggest that autopoiesis can be at least roughly characterized as collective autocatalysis plus spatial individuation. Although some mechanism of spatial confinement or concentra¬tion is probably necessary to the effective operation of any collectively autocat¬alytic reaction network, autopoiesis requires, in addition, that the mechanism for maintaining this confinement should itself be a product of the reaction net¬work – and should thus (?) be capable of separating or individuating otherwise identically organized networks. I suggest an informal heuristic test to discrim¬inate the (merely) collectively autocatalytic from the (properly) autopoietic. Finally, in the light of this, I review a variety of published abstract or model sys¬tems, Alchemy, α-universes, Tierra, and SCL.

Computational autopoiesis – the realization of autopoietic entities in computational media – holds an important and distinctive role within the field of artificial life. Its earliest formulation by Francisco Varela, Humberto Maturana, and Ricardo Uribe was seminal in demonstrating the use of an artificial, computational medium to explore the most basic question of the abstract nature of living systems – over a decade in advance of the first Santa Fe Workshop on Artificial Life. The research program it originated has generated substantive demonstrations of progressively richer, lifelike phenomena. It has also sharply illuminated both conceptual and methodological problems in the field. This article provides an integrative overview of the sometimes disparate work in this area, and argues that computational autopoiesis continues to provide an effective framework for addressing key open problems in artificial life.

This paper summarizes some initial empirical results from a new computer model (artificial chemistry) which exhibits spontaneous emergence and persistence of autopoietic organization. the model is based on a system originally presented by Varela, Maturana, and Uribe. In carrying out this reimplementation it was found that an additional interaction (chain-based bond inhibition), not documented in the original description by Varela et al., is critical to the realization of the autopoietic phenomena. This required interaction was rediscovered only following careful examination of (unpublished) source code for an early version of the original model. The purpose of the paper is thus two-fold: firstly, to identify and discuss this previously undocumented, but essential, interaction; and secondly, to argue, on the basis of this particular case, for the importance of exploiting the emerging technologies which support publication of completely detailed software models (in addition, of course, to conventional publication of summary experimental results).

Key words: autopoieses, artificial life, artificial chemistry, origin of life