Maybe this is what happened with Walt and the polar bear after reading the comic. * It might be that, in a previous iteration of the universe, Walt found the comic book with the polar bear, but because he's "special" (perhaps because Jacob selected him?) the universe actually reformatted itself to be consistent with his vision of a polar bear, and the Dharma Initiative's decision to experiment on polar bears is in some way "meta-caused" by Walt's use of his powers in the previous universe. Maybe that's how all the weird stuff that Walt does happens.