"It's an odd position to find oneself in apropos one's own work- to still like it, but not to agree with it. But I've been thinking things over: a poem is not an academic paper..."
One of the reasons I've only been skimming rec.arts.sf.composition at the moment and posting only rarely is that the group does seem to keep bogging down in arguing about what's "true" in this world and in the present day.
I like poliphilo's poem, though I also don't believe in it. But I do feel that it captures something of what people might have believed once, or what people might believe in an alternate universe. It doesn't bother me that it isn't "true". I read and write fiction about stuff I think is amazing or beautiful or frightening, but I really don't believe in most of it.
Art doesn't necessarily have to be "true" in order to reveal some aspect of truth about people and too much scientific rigour can extinguish the vital spark of an SF or fantasy story.