[Charley Lineweaver](http://www.mso.anu.edu.au/~charley/) is based at the [ANU](http://www.anu.edu.au/) and researches planetary science, astrobiology and cosmology. In some recent speculation, he has made some controversial theories on redefining life. While I agree with his main argument, I don’t feel that that the qualities that he is identifying are sufficient.His main thrust is to define life as anything that qualifies as a *far-from-equilibrium dissipative system*. This would be a system that feeds on the free energy associated with the gradients in the environment. An example would be a storm system, being a dissipative system because it feeds on the free energy of air pressure, humidity and thermal gradients in its wider environment. The storm is dissipating the free energy in the environment and bringing it closer to equilibrium.
Similarly, biological systems, like mammals, dissipate chemical energy and move the general environment closer to equilibrium as a natural function of living.
I think that there is merit in this quality – living systems certainly *feed* on things in their environment. Charley claims that this is a measurable characteristic and this does present benefits. But I think that he is missing a couple of other characteristics that are important.
The more important of the two is that a living system needs to be able to replicate or reproduce in some fashion. While a dissipative system is dynamic, which is an important aspect, it also needs to be able to create a new system that shares many of its characteristics. I don’t feel it is necessary that all of these characteristics pass along, but it does need to be able to transmit some of its identity to a new generation, to allow another system to exist once the parent system has ceased its ability to feed on the external environment.
If the parent system is not ever going to exceed the carrying capacity of its environment, or exceed the long term integrity of its own structure, then it seems to me that we are talking about an *immortal* system. If it is merely *mortal*, I think that for a system to live, it needs to pass on to a new generation, asexually or sexually.
The less clear aspect, for me, is the idea of genesis, regardless of mortal or immortal. The living system has to have a life-cycle. Perhaps in the case of the immortal case, it could be that it only has one end of the life-cycle closed, the time in the general environment before the living system has taken form sufficient to be able to dissipate free energy. But there still has to be a genesis, and possibly a death event, which should occur after the replication if the life form is to be a successful one.
Given the above, we still don’t need to worry about *intelligence* or *free will*. Awareness can merely be sensing the energy gradients in the external environment. Another interesting tension is that for digital life. It seems to me that digital life, given these conditions, is not real life because it doesn’t dissipate free energy in the environment in any fashion different to any other data encoded in an electronic system.