Revisiting the Gaia Hypothesis: Maximum Entropy, Kauffman’s‘Fourth Law’ and Physiosemeiosis

Recently, Kleidon suggested a restatement of the Gaia hypothesis based on Maximum Entropyapproaches to the Earth system. Refuting conceptions of Gaia as a homeostatic system,Gaia is seen as a non-equilibrium thermodynamic system which continuously moves awayfrom equilibrium, driven by maximum entropy production which materializes in hierarchicallycoupled mechanisms of energetic flows via dissipation and physical work. I propose torelate this view with Kauffman’s ‘Fourth Law of Thermodynamics’, which I interprete as aproposition about the accumulation of information in evolutionary processes. Then, beyondits use in the Kleidon model, the concept of physical work is expanded to including work directedat the capacity to work: I offer a twofold specification of Kauffman’s concept of an‘autonomous agent’, one as a ‘self-referential heat engine’, and the other in terms of physiosemeiosis,which is a naturalized application of Peirce’s theory of signs emerging from recentbiosemiotic research. I argue that the conjunction of these three theoretical sources, MaximumEntropy, Kauffman’s Fourth Law, and physiosemeiosis, allows to show that the Kleidon restatementof the Gaia hypothesis is equivalent to the proposition that the biosphere is a systemof generating, processing and storing information, thus directly treating information as aphysical phenomenon. I substantiate this argument by proposing a more detailed analysis ofthe notion of hierarchy in the Kleidon model. In this view, there is a fundamental ontologicalcontinuity between the biological processes and the human economy, as both are seen as informationprocessing and entropy producing systems. As with other previous transitions inevolution, the human economy leverages the mechanisms by which Gaia moves further awayfrom equilibrium. This implies that information and natural resources or energy are not substitutes,i.e. the knowledge economy continues to build on the same physical principles as thebiosphere, with energy and information being two aspects of the same un