I may be generalizing here, but it seems to me the folks over at Brain Pains are both strong content externalists and proponents of qualia. I’m trying to figure out how they’d go together. I’ll be honest and say today is the first time I ever thought about it and I just don’t see how they’d co-exist. I’m sure there is a good explanation, but…
Recall, content externalism is the belief that mental content is constituted in part by external factors. Following Putnam’s twin earth, if water is xyz on another planet and not h2o, then the two thoughts of water by a creature in either situation with identical internal states are different. The attraction, I suppose, it to ward off relativism. If a first intension {water-h2o} is wrong, then a secondary intension {xyz} closes the deal independent of our faults, so we don’t have to worry about the “world changing” {Kuhn} as our scientific theories update.
Now, I don’t know what Putnum explicitly thought about qualia, but I do know he invented functionalism, so that implies he either reduced or eliminated qualia. But what about for those who believe in nonreductive or nonphysical qualia and content externalism?
– qualia are part of our mental content
– qualia are indubitable to us
– mental content is external
These premises result in at least what really seems like a contradiction. If “red” is red because it seems that way to me and nothing more {qualia} then how can it be ‘outside the head’ {external}?
Worldly Living 
P.S.
I realize Putnam’s externalism was semantic but I think it’s close enough.
Ok, here’s probably the standard answer…from Dretske:
“2. Qualitatively identical twins. Dretske does not so much argue for phenomenal externalism as rely on thought experiments to show that if you are a conceptual externalist, you have no reason not to be a phenomenal externalist too. One such experiment involves Twin Earth, where, as you may have heard, the common, clear, thirst-quenching liquid is not water but twater. The question is, does twater look to Twin Fred as water looks to Fred? Dretske thinks that whereas water looks like water to Fred, twater looks like twater to Twin Fred, and that looking like twater is different from looking like water. He thinks this because, assuming concept externalism, there is a difference between what Fred and Twin Fred think, respectively, about what water and twater look like-and each is right about what that is. Hence Fred and Twin Fred’s experiences are phenomenally different.”
http://userwww.sfsu.edu/~kbach/Dretske.html
a key sentence here:
“Dretske goes on to argue that introspective knowledge, at least of perceptual experience, is not a matter of looking inward, at distinctively experiential properties, but of conceptualizing properties already being experienced.”
Huh. So the phenomenal could be uh, structured by concepts?