Steve wrote:
I don't think people *do* understand them [[complex systems]] in their totality; that's why I mentioned subsystems.
I beg to differ. In my line, understanding complex systems in their totality is all part of a day's work, though I admit it's a reasonably rare skill. Someone I used to work for said that when she needed to write something really challenging (and we're talking about papers for academic journals here), she'd go home and have a couple of G&Ts and then write the first thing that came into her head. I think that was her way of freeing her brain to understand things at a higher level than the bog-standard logical one.
And a town planner, who reroutes roads around buildings to give better traffic flow, can screw things up in exactly the same way as a programmer, when, say, that tiny through-road gets flooded.
And a really good town-planner would close his/her eyes, then say 'no that doesn't work, there's a bottleneck there'.