“Unlike physical or chemical dissipative structures, in which patterns of dynamic order form spontaneously, but whose stability relies almost completely on externally-imposed boundary conditions, autonomous systems build and actively maintain most of their own boundary conditions, making possible a robust far-from-equilibrium dynamic behavior.”
“A big stone in the river holds water from flowing, and some bacteria ferment milk to produce yoghourt. Although both systems do something, we do not call the stone an agent. The difference between the two cases is not in the degree of change operated by one or the other, but in the consequence of that change: only in the latter case does the change contribute to the maintenance of the performer of the action.”
Ruiz-Mirazo, Kepa & Moreno, Alvaro (2012). “Autonomy in evolution: from minimal to complex life”. Synthese 185 (1), 33-34.