Earlier quoted context omitted.
It won't, it will show that there are no normative questions. (exaggerated on purpose, of course, but it's The Final Frontier - once we know how the brain works, we will have a real insight into the nature of morality and we will have 'proof' for the objective nature thereof - all this IMNSHO of course ;) )
I think you're confused. There are clearly normative questions ; "Should I do X?" for any value of X is a normative question. You might have intended to contend that there are no normative facts : that there is no "right answer", as it were, to normative questions, merely what we choose to do. However, this is not something that science can prove, at least without adding the claim that the only facts there are are ph…
My point was that there is nothing science won't be able to prove; and that there is only physical reality, and facts, and that once we crack the 'code' (as in 'security code', not 'programming code', although in another discussion I'd posit that it's both) we will learn about the fundamental nature of morality - as humans perceive it; it's exactly this realization (that moral issues stem from interpretation by man) that will show that most things we consider 'moral issues' really aren't.
(the above may make it seem that I'm a moral relativist but I'm not - au contraire, once we peel away the human-induced layers of morality we will find the fundamental nature of it at the core)