Apparently I have some questions to answer.
First of all, thanks to Thomas for the questions. I am obviously writing an entire book to answer these and similar questions, but it is always helpful to have them posed by someone else. I don't necessarily identify with the way in which they are posed, but this is actually a good thing.
Do you believe in duende?
I believe that people use the term in a way that is meaningful to them. An analogy might be the word "pocket" in drumming. I believe musicians recognize when a drummer is playing "in the pocket," or has a "deep pocket." It is semi-mystical, because it is a subjective "feel" and not an absolute measurement, but I think it has a subjective reality that cannot be disdained. The duende is not the pocket, but it is in the same category of terms. You can probably think of other concepts similar to this if you try hard enough.
Usually, the "do you believe in ... " question is not asked of things that really exist in a tangible way. So, "Do you believe in Canada" is nonsense question for most people. Everyone believes that there is a country called Canada. So you would be likely to interpret the question as "Do you believe Canada has a promising future as a nation state?" By the same token, assuming that the God Odin does not exist, "Do you believe in Odin" is a nonsense question of a different sort. It is not really a question of believing whether Odin exists, or not, but of worshipping him. If you worship a deity, then the existence is kind of subsumed under that, not vice-versa. By the same token, I think the question of whether someone believes in "God" is rather question begging. What does one mean by God in that question, exactly? A whole theology already has to be in place for the question to even make sense. Another way of saying this is that in any religious practice, the language used in that practice is meaningful and hence possessing a subjective reality to practitioners. So the Dharma could be as real as the pocket. The mistake is giving those concepts empirical existence outside of the frames in which they are meaningful.
There are a category of things that might or might not exist, and in that case it makes sense to ask whether tbose things exist. For example, I do not believe the original Lorca poem for Creeley's "After Lorca" exists. In other words, I do not believe his poem is the translation of an actually existing poem written by Lorca. That is an empirical question, and hence my belief could be falsified if someone found documentation for this poem. That is the most meaningful way to talk about the existence of things.
I've gotten off on a tangent, but not really. Asking whether duende or the pocket exist is asking, really, whether people who use language like this use it in a meaningful way. I believe that yes, they do, and hence I believe in the duende, but I do not worship it. In other words, I do not confuse an aesthetic practice with an empirical reality that has an absolute existence outside of that context.