One of the challenges of naturalism is that, taken strictly, it seems to rule out the existence of ideas or concepts as transcendent entities. Even for scientifically minded individuals, some concepts seem to exist in the sense of our discovering them, even though they are not part of nature. The prototypical examples are in the arenas of logic and mathematics.
I have often been critical of the disproportionate focus in academic philosophy on concepts and language as things of primary analytical interest, as opposed to their being derivatives of our (very complex) interaction with the rest of the natural world. But there are persuasive arguments that some of these concepts seem stubbornly non-reducible to nature.
It occurred to me that a way to naturalize these seemingly platonic concepts would be to picture them as gaining traction from a larger multi-verse. Science increasingly points us to the idea that our observable universe is a part of a larger complex of universes, each with potentially different characteristics along certain dimensions. As we and our world co-evolve, perhaps we reach toward ideas that do find a natural incarnation somewhere in this much larger meta-world.