From a philosophical standpoint, the starting line for "complex" is in something you take it upon yourself to pursue. The world we inhabit has a complex ecosyst

From a philosophical standpoint, the starting line for "complex" is in something you take it upon yourself to pursue. The world we inhabit has a complex ecosystem, physics, etc; our study of it is far from complete. But every time we learn something about it a technical advance becomes possible. Nobody has to keep the gears turning in this vast society. But someone at some point decided it was worth it to create those gears, without answering all the how's and why's: basic science doesn't tell us how to engineer things, only that we have ways of dong so. So the "accident" of it emerges like a freeway pileup, from different domains of study colliding. And with computing being the workhorse technology for everything now, the crashes are so frequent as to be unremarkable.