On the existence of the muses...

I'm kind of an ontological relativist... I figure any paradigm that satisfactorily describes a given reality in a coherent, self-consistent way without breaking its own internal rules or denying self-evident reality is a fair choice.

No paradigm is perfect. You're looking for an analogical handle to mentally manipulate complex conceptual interrelationships. Whether you talk about subconscious autonomic intellectual processes or the muses, it's having a good grip on what you're talking about that counts.

From that perspective, I often talk about the muses because that's really how it feels. Now, mind you, my notion of the muses is based on information theory -- but then, so is my notion of sentience, identity,  sense of self. Since I don't, in a very real sense, believe in me, as some sort of unitary entity, it's pretty easy for me to be flexible about the muses.