Self-organization at the origin of life

The concept of an (M, R) system with organizational invariance allows one to understand how a system may be able to maintain itself indefinitely if it is coupled to an external source of energy and materials. However, although this constitutes an important step towards Understanding the difference between a living and a non-living system, it is not clear that an (M, R) system with organizational invariance is sufficient to define a living system. To take a further step towards defining what it means to be alive it is necessary to add to a simple (M, R) system some property that represents its identity, and which can be maintained and modified in subsequent generations. (c) 2007 Elsevier Ltd. All rights reserved.