Chemistry is a "solved problem" granted we don't have a computer that can run the simulation for large organic molecules, but it has ZERO secrets. Now, DNA runs on the cellular machinery, but that is also running on the well known chemistry rules so adding up the instructions required to define a cell + DNA = something of a lower bound on the required complexity to create a brain. The idea is if you know how complex a solution to the problem is, then you can use that complexity even if you are using a different approach to the problem.

IMO, it does not say much. I can't comprehend the limits of 50MB of heavily macroed and slightly buggy LISP code. It's simply not a meaningful metric. Edit: Also, in theory we could write a program which would simulate human level intelligence, but run far too slowly to be useful in any meaningful context.

PS: Findman had a wonderful description of chemistry as the search for rules of thumb to let people simplify the problem of simulating the physical equations.