Yup... this is starting to sound very familiar.
Just like Deep Thought told Lunkwill and Fook when he was about to tell them the answer to the question of life the universe and everything
Yes... but I suspect you really won't like it.
But here is something you can do with less undesired consequences.... read these articles.
Why don't you tell me why you think this settles the issue?
No reasonable person could deny that there's a correspondence between brain injury and behavior. Indeed, that correspondence is often a reason we consider the person not responsible for his actions. But it does not alter how we separate good from bad actions for those who appear morally responsible.
Let me put it another way. You think that the primary things to know about norms are the following:
(1) Which norms benefit the individual, society or species?
(2) Which norms do individuals tend to adopt?
(3) Which norms do society encourage?
Maybe a few others, but I think these would be up high on your list. Correct me if I'm wrong.
Now, let's talk about someone who commits some horrible act: a serial rapist, murderer, a tyrant who commits genocide, what have you. What judgments would you make about that person?
Would you say, "He has adopted very different norms than me. I'm curious whether he will experience reproductive success?"
Would you think, "He has not adopted the dominant norms of his society and hence does not function well in society. He is malfunctioning, like a teapot that leaks. This is, of course, not a moral judgment, but he functions less well than the average person?"
Would you think of his behavior solely in terms of evolutionary pressures? Because, I must confess, I tend to think of a person who commits genocide as a bad person. I know you can tell me an evolutionary story of why I tend to think that way, but as I reflect, I cannot shake the feeling that there is something fundamentally wrong about treating fellow persons abysmally. I cannot help but believe that a rational person sees himself as one among many, each valuable and each therefore worthy of consideration, and failure to treat others with at least some minimal decency is a great shame.
Oh, I could be wrong and you could be right. Might just be my particular brain structure has evolved in such a manner, and you happen to be clever enough to see through the tricks your own brain structure causes when considering great harms. But I need some argument as to why it's not even possible that these things matter, in an objective sense and not merely as a reflection of my evolutionary history.
And pointing out that brain-damaged folk act differently seems rather beside the point to me. They also may fail to do mathematics correctly, but I don't therefore conclude there is no objectivity to valid argumentation.