Selforganization in molecular and cellular networks.
Biological organisation rests on forces among material constituents which manifest themselves in two principal forms, namely as static-conservative and as dynamic-dissipative, the latter being responsible for selforganisational and regulatory behaviour. There is a unifying concept underlying such phenomena as selection, evolution, differentiation, morphogenesis, memory and learning which involes various forms of autocatalysis in open systems far from equilibrium. Examples are the steady turnover of selfreproducing molecules, which is the basis of selection and evolution at the genetic level, or the excitatory and inhibitory interplay of cells allowing for controlled growth and intercellular communication as encountered in the immune system or in nerve cell networks. Recent studies of the dynamics of systems far from equilibrium have revealed deep insights into the nature of biological organisation. This is exemplified by three model systems dealing with The modern understanding of conservative and dissipative structure provide a solid basis for an old morphological concept which - since ancient times - has been intuitively perceived: Gestalt, indeed, is not simply the sum of its parts, even if forces among the constituents - the stoics "pneuma" - are taken into consideration. Gestalt rather is a dynamical state dependent upon initial and boundary conditions of the material system in which it manifests itself.
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Max-Planck-Institut für biophysikalische Chemie, Göttingen, West Germany.