EXCERPT In a recent article published in the journal Life, astrobiologists Stuart Bartlett and Michael Wong proposed a new generalised definition of the concept of life.1 In their essay, the scientists define a new category of chemical processes which they call lyfe, broad enough to include a greater variety of ‘life as we don’t know it’. According to the authors, although terrestrial life is a physico-chemical phenomenon that manifests itself in the presence of liquid water, is based on organic carbon-based molecules, and maintains its internal order through the dissipation of energy, there may be many other forms of life, or rather lyfe, with very different characteristics. Their definition of lyfe is articulated around four fundamental characteristics: dissipation, autocatalysis, homeostasis, and learning. Dissipation, which we have already discussed, is the characteristic of those so-called dissipative systems in which order is maintained through continuous consumption of energy: these are ‘open’ thermodynamic systems which never reach a state of equilibrium, but are continuously traversed by a flow of energy. Our cells are an example of a dissipative system but, as we have seen, dissipation can also occur in completely inorganic systems, as in the case of Bénard convection cells, for example.…