Freddie DeBoer deflects Will Wilson's post:
[N]ot only does the giraffe not know how to understand electron spin; it does not know that there is such a thing as not knowing how to understand electron spin. It's not just that the giraffe can't answer the question, but that its limited consciousness is incapable of realizing that such a question might be posed. What might be the case, but we can't know, is that there are problems that we are similarly unaware of. If you'll forgive me for invoking Donald Rumsfeld, there are known unknowns-- the reconciliation of relativistic gravity with quantum mechanics; the Riemann hypothesis-- but there might also be unknown unknowns, things that we don't know we don't know. If this were true, it would undercut what Will is saying; it shouldn't surprise us that with time we solve the problems we apprehend, but it also shouldn't surprise us if there are questions we aren't even aware are questions. (You can add a "yet" to the end of that, if you're inclined.)
Wilson takes the point and salvages his larger argument.