[freehorse]

I do not think of complexity as one thing. Abstractions are about both hiding and exposing complexity at the same time. Different levels of abstractions can expose or isolate different part of complexity. Exposing parts of it in a way that they become amenable to your tools is as important as isolating other parts somewhere in the background. Essentially, this has to do with how well a given abstraction choice maps into the structure of the problem-space and the relationships there. The choice of which parts of complexity you isolate and which you expose is important. You probably do not want to deal with everything at once, but also usually you cannot avoid dealing with something.

The way I primarily see (and often like) type systems wrt complexity is as choosing which parts of complexity are important and exposing them (and rest being still there to deal with). There is a cognitive aspect to abstractions and complexity, irrespective even of IDEs, debuggers, compilers etc. I personally want my abstractions to make at least some sense in my head or a piece of paper in the way I think about the problem before even I start writing code. If the abstractions do not help me actually cognise about (some part of) the problem, they probably solve other problems, not mine.