A simple molecular system is described consisting of the reciprocal linkage between an autocatalytic cycle and a self-assembling encapsulation process where the molecular constituents for the capsule are products of the autocatalysis. In a molecular environment sufficiently rich in the substrates, capsule growth will also occur with high predictability. Growth to closure will be most probable in the vicinity of the most prolific autocatalysis and will thus tend to spontaneously enclose supportive catalysts within the capsule interior. If subsequently disrupted in (...) the presence of new substrates, the released components will initiate production of additional catalytic and capsule components that will spontaneously re-assemble into one or more autocell replicas, thereby reconstituting and sometimes reproducing the original. In a diverse molecular environment, cycles of disruption and enclosure will cause auto-cells to incidentally encapsulate other molecules as well as reactive substrates. To the extent that any captured molecule can be incorporated into the autocatalytic process by virtue of structural degeneracy of the catalytic binding sites, the altered autocell will incorporate the new type of component into subsequent replications. Such altered autocells will be progenitors of “lineages” with variant characteristics that will differentially propagate with respect to the availability of commonly required substrates. Autocells are susceptible to a limited form of evolution, capable of leading to more efficient, more environmentally fitted, and more complex forms. This provides a simple demonstration of the plausibility of open-ended reproduction and evolvability without self-replicating template molecules or maintenance of persistent nonequilibrium chemistry. This model identifies an intermediate domain between prebiotic and biotic systems and bridges the gap from nonequilibrium thermodynamics to life. (shrink)

The Systems Theory is a complex theory (yet it is not identical to recent theories of complexity). The intention of this qualification is to demonstrate that the concept of a system is a complex basic concept of scientific thinking. This means that it is defined in terms of various elementary basic concepts brought together in its explication. The definition given by Von Bertalanffy to the concept of a system employs conceptual elements coming from at least five prominent conceptual clusters. In (...) order to highlight the nature and interrelations between these clusters this article focuses upon perennial philosophical issues which present themselves within the definition of a system. They are those of stability and change, the one and the many (unity and multiplicity), the whole and its parts, and the relation between the material and the vital. An analysis of the interrelations between these clusters provides the basis for an assessment of the scope and limitations Von Bertalanffy's concept of a system. S. Afr. J. Philos. Vol.21(3) 2002: 163-179. (shrink)

Stem cells have the capacity both to self‐renew and to give rise to differentiated progeny, and are vital to the organization of multicellular organisms. Stem cells raise a number of fundamental questions regarding lineage restriction and cellular differentiation, and they hold enormous promise for cell‐based therapies. Here I propose a theoretical framework for stem cell biology based on the concepts of autopoiesis (self‐production) and complementarity. I argue that stem cells are pivotal in the self‐production of the organism and that we (...) need complementary approaches to understand their probabilistic behavior. I discuss how this framework generates testable hypotheses regarding stem‐cell functions. BioEssays 26:1013‐1016, 2004. © 2004 Wiley Periodicals, Inc. (shrink)

A central difficulty in the way of understanding Spinoza's metaphysical system is that of reconciling two apparently contradictory theories of the causation of finite modes found in his Ethics. The easiest way to present the problem is to place these two accounts side by side.A. All things which follow from the absolute nature of any attribute of God must forever exist, and must be infinite; that is to say, through that attribute they are eternal and infinite. A thing which has (...) been determined to any action was necessarily so determined by God. Together, these propositions entail that God is a necessary and sufficient condition for the occurrence of any action, and that anything so determined is eternal and infinite. Compare these implications with the following.B. An individual thing or a thing which is finite and has determinate existence cannot exist nor be determined to action unless it be determined to existence and action by another cause which is also finite and has a determinate existence; and again this cause cannot exist nor be determined to action unless by another cause which is also finite and determined to existence and action, and so on, ad infinitum. (shrink)

In this paper we criticize the “Ashbyan interpretation” (Froese & Stewart, 2010) of autopoietic theory by showing that Ashby’s framework and the autopoietic one are based on distinct, often incompatible, assumptions and that they aim at addressing different issues. We also suggest that in order to better understand autopoiesis and its implications, a different and wider set of theoretical contributions, developed previously or at the time autopoiesis was formulated, needs to be taken into consideration: among the others, the works of (...) Rosen, Weiss and Piaget. By analyzing the concepts of organization and closure, the idea of components, and the role of materiality in the theory proposed by Maturana and Varela, we advocate the view that autopoiesis necessarily entails self-production and intrinsic instability and can be realized only in domains characterized by the same transformative and processual properties exhibited by the molecular domain. From this theoretical standpoint it can be demonstrated that autopoietic theory neither commits to a sharp dualism between organization and structure nor to a reflexive view of downward causation, thus avoiding the respective strong criticisms. (shrink)