I was going to respond to Clayton as soon as I got the time. And the water=H20 example occurred to me when I read what he wrote.
But look at how the water case went historically. We started calling something water that had certain phenomenal properties. We were prepared to call anything water that had those properties. We figured out that the only thing that ever had those properties had a particular chemical structure. We melded the idea of water with the idea of having just that chemical structure. In other words, it looks as if when the discovery was made, language made a shift to the chemical structure conception. The class of objects now referred to as water changed intension but extension remained the same.
When we get to intentional matters, we are being told that we are not going to get a single brain-structure that will be present in all cases of, say, thinking about Obama. Correct me if I'm wrong about this, but if we examined everybody's brain who is thinking about Obama right now, neuroscience would not be able to go in and say "Aha. There it is. The Obama configuration. That's what he's thinking about. Hmmm. This looks like a Republican brain, since his endorphins drop every time he thinks about Obama. You don't get that with a Democratic brain."
So I'm not sure these water examples help at all.
And then you have the problem of non-normative information entailing something normative. If you don't think you can derive "morally good" from physical configurations, why do you think you can get "thinking about Obama" from those same configurations.
I think the prospects of getting an entailment from the left hand side to the right hand side are not good.