Thanks to some pointed questions from my dear friend, Chris Krull, I am heading back to first principles and trying to clarify what I'm really trying to protect.
Chris very correctly pointed out to me the dangers of saying something was "universal" in the sense that it implies that someone who for some reason doesn't experience a certain thing might be categorized as less than human. That's an excellent point.
I don't think that I believe in a musical universalism that can be brought down to some sort of 1:1 semiotical correspondence. I don't think that, for example, a major 7th has some specific, prescriptive meaning that works like a magical amulet to coerce some sort of emotional response from a listener.
Ultimately though, what I'm really trying to defend is the ability of people everywhere to communicate. In the same way that I believe that languages can be translated, I think we can learn to understand other musics. I also don't necessarily believe it takes years of cultural immersion to grasp it.
Let me say it this way. In the classic arguments for solipsism, I can't be sure that when I'm giving the ostensive definition of the color green to a child that the child is experiencing the same thing. That gets even more complicated when we want to talk about more difficult concepts like "love" or "father". Peoples definition are compiled from a sometimes terrifying set of circumstances when it comes to words like that. I think that I can actually communicate and translate my "love" and "father" to another. It may take a little work. As I said in the Facebook commentary, it takes "will and grace" for the magic of communication to actually occur.
I think it's true for music too.