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 physical facts. You're basically suggesting that we open up people's heads, look around, go "Nope, no norms here!" and take that to be evidence that they don't exist. This is problematic at best, since were they to exist, normative facts would seem to have properties quite at odds with physical facts, and your assertion starts to look question-begging.
Metaethics is not my area, so I'm afraid all of this is rather rough and ready, but the SEP article [1] is a pretty decent starting point.
Yes of course there's the distinction between the normative question and the underlying reality that question is about; my point doesn't require a distinction so I found it useless to make it and just went with the phrasing of the post I was replying to.
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)
Neurology and related sciences can help illuminate what our interests are, but cannot resolve the moral problem of what to do when those interests come into conflict. Science can tell me what kind of diet a child needs to grow into healthy adulthood, but it can’t tell me under what circumstances it would be moral to take money from the wealthy (or, heck, the middle class) in order to feed starving children.
but it can’t tell me under what circumstances it would be moral to take money from the wealthy (or, heck, the middle class) in order to feed starving children.
Sure it can. Take north western Europe, notoriously secular (when compared to the US) yes quite socialist with an extensive social safety net. Economics, sociology, etc, all help you identify what you need to do to reach what ever goals you are aiming for.
And ethics and fairness have been studied and are well known in other social species, like the great apes. They are not uniquely human.
Morality is just the formalization of a whole set of instinctive emotional desires for fairness. Most often it is enforced by using another emotional foundation, the respect for alpha leaders, as in it is God's law you do this and that.
There is no domain which will eternally be out of the reach of reason and science, not morality, not love, not spirituality, nothing. I find this wonderful!
I have an instinctive emotional desire to keep what I possess. You have an instinctive emotional desire to feel compassion for someone who is suffering. Because of your emotions, you want to raise taxes on my property to support the poor. Because of my emotions, I want my taxes to stay the same, if not lower. How can science decide between us?
Social game theory is complex but not impossible to understand. If it were impossible, countries not ruled by the pope any more would be all like Somalia.
Game theory helps you decide, given a game with certain rules and a scoring metric, how to maximize your score. Political philosophy helps you choose the rules of the game.
