We are not. We're determining whether particular classes of turing machines halt, and we're determining whether particular theorems hold in ZFC (and doing a lot of mathematical work which is neither). This is not evidence that the human brain is super-turing, because these are computable problems.
> It does not, for example, rule out whether you can write a Halt procedure for no-input Turing Machines with N states. In fact we have already written them for N=1,2,3,4.
Turing didn't, but later work does. BB(748) is known to be independent of ZF. The real bound is likely much lower.