Complexity, emergence and the origins of life

Abstract
Living organisms, as we know them today, are extremely complex systems and it is highly probable that the same situation prevailed for the first living systems that have appeared on earth. Life is no doubt associated with the emergence of global properties different form those of any of the components of a living system. In order to understand the role played by complexity and emergence in the appearance of life it is no doubt essential to define unambiguously what the term life means. Such a definition, however, is probably impossible to offer and the only sensible approach to our problem is to define what living organisms are or, put in other words, define the main features of living systems.