Hmm, but isn't this conflating "learning" in the sense of "learning about the world/nature" with "learning" in the sense of "learning behaviours"? We know the brain can do the latter, it's whether it can do the former that we're interested in, surely?

IOW, it looks like you're saying precisely that the brain is not a ULM (in the sense of a machine that learns about nature), it is rather a machine that approximates a ULM by cobbling together a bunch of evolved and learned behaviours.

It's adept at learning (in the sense of learning reactive behaviours that satisfice conditions) but only proximally adept at learning about the world.