> So, what, "complexity isn't a sufficient explanation," and _also_ "it's perfectly reasonable to believe it's the result of processes we don't understand?"

Those are not conflicting arguments.

The former means that we understand all the processeses, but they are complex, therefore we don't have enough brain/compute power to properly model it.

The latter means that we don't understand some of those processes, so we need additional theories that explain them.

One can dismiss the first while finding the second plausible.

I suppose complexity defines to me as something that's inherently hard to understand. The definition of "complex" is "difficult to understand." The move I don't agree with is proceeding to posit "because we don't understand them yet, there must be something special about them."