06 May 2023 19:15

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.