John Wilkins has a typically lucid post addressed to the question: What is nature? He's not himself trying to come up with an answer, but rather is interested in how the question arose. After suitable citation (including one of his favorites, J.S. Mill) Wilkins arrives at:
The “Arcadian” vision of nature was something for the benefit of humanity, decreed by a benevolent deity. So our separation from nature was based upon our agrarian, civilised, theistic vision of ourselves.
In recent years, we have seen a trend to “naturalise” humans, however. We have discovered the natural causes of mental activities and failures, of our physiology, our evolution, and even our abilities to know the world.
He concludes that "In the end our idea of nature is incoherent or needs to be revised to be coherent." And, crudely put, object-oriented ontology rides that incoherence.
Let's conclude this brief note by looking at his opening paragraph, where he tells us there are two kinds of naturalism: "ontological naturalism (the view that all that is, is natural) and methodological naturalism (the view that all that can be known can be known via natural methodologies such as scientific method)." His post is about the former.
As for methodological naturalism, it is in THAT sense that I talk of a naturalist literary criticism. I am not making an ontological claim that literature is more or less just like atoms, thunderstorms, and toads – though, who knows, it might be – but that we can understand how literature works through natural methodology. Roughly speaking, both the literary Darwinists and the cognitive rhetoricians and poeticists espouse something of a naturalist methodology as well, though one that doesn't emphasize description. And the Darwinists may well espouse ontological naturalism as well; they probably do.
But that is only speaking roughly. More precisely...well, that's likely to go on and on. Maybe later.