06 Aug 2021 09:53

A definition would be nice. So would an ordinal if not a cardinal measure. Is it clear that humans are more complex than whales? Than chimpanzees? Than termites? Than termite mounds?

Is there any trend towards greater complexity over time among living things? On the Earth as a whole? The universe as a whole? Is there any deep explanation (élan vital anyone?) or can it be accounted for by the usual suspects --- natural selection, "plenty of room at the top," chance? --- Even if we do come up with a measure of complexity, it will be very difficult to apply to the fossil record, since the soft parts are pretty well gone, and so we can't know (much) about the innards of the brain, or the immune system. (In fact, could you infer the existence of immune systems from the fossil record? This is important, since it's complex if anything is, and if we can't infer it, how do we know there weren't other things, also confined to the soft tissues, which weren't comprably complex?)

The "sciences of complexity" are very much a potpourri, and while the name has some justification --- chaotic motion seems more complicated than harmonic oscillation, for instance --- I think the fact that it is more dignified than "neat nonlinear nonsense" has not been the least reason for its success. --- That opinion wasn't exactly changed by working at the Santa Fe Institute for five years.

See also: Adaptation; Agent-based Modeling; Artificial Intelligence; Artificial Life; W. Ross Ashby; Biological Order and Levels of Organization; Cellular Automata; Chaos and Non-linear Dynamics; Cognitive Science; Collective Cognition; Complexity Measures; Cybernetics; Darwin Machines; Developmental Biology; Dissipative Structures; Edge of Chaos; Emergent Properties; Ergodic Theory; Evolution; Evolution of Complexity; Evolutionary Computation; Evolutionary Economics; Information Theory; Institutions and Organizations; Learning in Games; Machine Learning, Statistical inference and Induction; Multi-Agent Systems; Neural Nets, Connectionism, Perceptrons; Neuroscience; Nonequilibrium Statistical Mechanics and Thermodynamics; Pattern Formation; Physics of Computation and Information; Physical Principles in Biology; Physics; Power Law Distributions and Long-Range Correlations; Ilya Prigogine; QWERTY; Random Boolean Networks, Nk Networks; Self-organization; Simulations; Statistical Mechanics; Tsallis Statistics