Why do complex systems exist in a universe bound to adhere to the 2nd Law of Thermodynamics?
Ilya Prigogine discovered in the 20th century that, when additional considerations are taken into account alongside established laws of dynamics, the statistical properties of large collections of particles give rise to states in which information, organization, structures (or whatever you’d like to call low entropy phenomena) are produced without further manipulation from an outside organizing influence. The ability to organize without this influence is reflected in a principle which states that systems out of equilibrium tend toward dynamic steady states after an initial period of fluctuation through transient states; the archetypal example being a whirlpool created by draining water in a tub, a non-equilibrium system wherein free energy and particles are exiting the system. After an initial period of random turbulence, the movement of individual water molecules near the drain become increasingly correlated until a whirlpool is formed. As to what keeps structures in place longer than the transient states from which they arose, Prigogine found that, for systems near but still out of equilibrium, the thermodynamic potential that was being minimized was entropy itself. While later research from scientists building off his work showed that far-from-equilibrium systems tended towards states that maximize entropy, these systems still minimized entropy compared to the transient states from which they arose.
Prigogine’s work demonstrated that, beyond their original nascency from transient states and their associated timescale, these ordered systems could maintain themselves as long as the non-equilibrium conditions could be kept consistent (i.e. not producing additional bifurcation of accessible states or approaching general equilibrium), their timescale now proportional to their separation from other bifurcation points. This timescale is dependent on the system at large and may vary from as little as the timescale of a whirlpool and as large a timescale as the ongoing revolutions of earth’s molten metallic core which produce our radiation-shielding magnetosphere.
As useful as longer scale non-equilibrium systems are, again pausing to reflect on our vital relationship with our magnetosphere, the systems that are driven by time-varying energy resources (e.g. the sun, underwater thermal vents, etc.) and have bifurcation points that allow them to enter new steady states as the energy resources vary are the ones that emerge with the robustness to evolve and survive, adjusting to longer scale changes. Alongside adaptability, physical systems that manage to create barriers to entropy survive longer and may gain more adaptive capacity in the process. These barriers to entropy may include external structures to shield established steady states from non-essential outside influence (e.g. prototypical cell membranes), an ability to solidify momentarily non-operative processes (e.g. keeping essential molecules like protein and DNA crystalline when not in use), or even an ability to manipulate itself or the environment into producing the favorable low-entropy states a system needs in order to persist (e.g. a sunflower turning to face the sun or a newborn crying for its mother’s milk).
It is the interplay between the universe’s ability to have pockets of disequilibrium, it’s propensity to select for non-equilibrium steady states (as opposed to perpetuating transient states) via the minimization of the entropy potential, and systems’ robustness for adaptive self-preservation, in lieu of shifting environments, that ultimately give rise to the increasingly complex systems we see in our everyday world, just as long as we maintain a healthy out-of-equilibrium condition within our local environment, here on our friend, the Earth.
