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TopSelf-Organization And Work In Biological Systems
In this paper, we attempt to understand semiosis in terms of self-organization. Unfortunately, nearly every discussion of self-organization invents its own terminology, which can lead to significant confusion. Here, we will mostly follow the conception of self-organization developed by Terrence Deacon in his 2012 book, Incomplete Nature. We will, however, avoid his idiosyncratic terminology as much as possible. Our aim, and Deacon’s, is to show how we might account for meaning, starting from thermodynamics.
Everything in nature, and presumably everything in the universe, follows the laws of thermodynamics. According to the second law of thermodynamics, closed physical systems will tend toward an equilibrium state that is maximally disordered. This law can be understood using two intuitive examples: food coloring that enters a glass of water as a single, highly ordered droplet gradually spreads to color the entire glass; the carbon dioxide that animals exhale does not hang around their faces, but dissipates through the entire room. For order or organization to be maintained—that is, for a system to remain at a non-equilibrium state—energy must be expended or dissipated. For instance, take the vortex that forms when a toilet is flushed. The order that characterizes the water vortex only lasts until the potential energy from the water in the tank is expended. Expending energy to maintain the vortex, or to maintain any organization for that matter, reflects work (in the technical sense used in physics). What this energy expended as work does is both order and constrain the possible ways in which the components of a system can behave, so that, to continue with our example, almost all of the water molecules move in a helical pattern instead of any of the other possible ways they might move. In open non-equilibrium systems, therefore, when work is being done, energy is being expended, and this energy dissipation creates constraints on the components of the system that last only as long as work is being done to keep these constraints in place. The constraints allow for organization to exist, including the kind of self-organization one sees in the vortex in a flushing toilet and in the many other examples of spontaneous order described in the literature on self-organization and complexity. (Note that Deacon calls these systems ‘morphodynamic’; most everyone else calls them ‘self-organizing’ or ‘complex’ or ‘dissipative’.)
A common question that is asked by those who initially learn of the second law of thermodynamics is: how can there be so much biological order on Earth (i.e., humans, animals, plants, etc…) if all systems evolve towards an equilibrium state that is maximally disordered (i.e., has maximum entropy)? Isn’t this order in violation of the second law of thermodynamics? The short answer is no. This is because the earth and all biological systems are not closed systems, but rather are open to a flow of energy. Indeed, the Earth’s surface is constantly bombarded with energy from the Sun, with this constant influx of energy keeping the surface of the Earth in a non-equilibrium state, enabling ordered phenomena such as bacteria, oak trees, and Elvis impersonators. However, it is important to keep in mind that self-organizing systems such as these are always temporary, and use up the energy and dissipate the constraints that enable their existence over time (sometimes on a short or sometimes on a long time-scale). The vortex dissipates the potential energy; trees use up the nutrients in the soil; Elvis impersonators eat all the cheeseburgers; and so on.
Sometimes, as is the case with all living things, multiple non-equilibrium dissipative self-organizing systems maintain one another’s constraints. The paradigmatic case of this, discussed in detail by Maturana and Varela (1980, 1987) is the cell. The self-organizing network of reactions that are the cell’s metabolism, among other things, maintain and repair the cell wall. At the same time, the cell’s wall is a selectively permeable boundary around the metabolism, maintaining chemical concentrations at the right levels for the reactions that make up the mechanism. The cell wall and metabolism act so as to constrain one another. The wall constrains the movement of the chemicals inside the cell and in its environment so that the metabolism continues. At the same time, the metabolism repairs breaches in the wall so that the chemicals that make up the wall continue as part of the cell wall. Maturana and Varela call systems like this ‘autopoietic’ or self-creating/sustaining; Rosen calls them ‘closed to efficient cause’ (1991, 2000); Swenson and Turvey (1991) call these systems ‘autocatakinetic’; Deacon calls them ‘teleodynamic’.