.. opens up a world and at the same time sets this world back again on earth, which itself only thus emerges as native ground.
What Heidegger means by this is not self-evident. In fact, Heidegger's philosophy often seems to be intentionally obscure. Nevertheless I will do my best to clarify what is being posed here, because the theory raises some interesting questions about the possibility of an all-encompassing idea of art.
Before we delve into this larger theory, it’s important to know what Heidegger means when he uses the terms ‘world’ and ‘earth’. The idea of ‘world’ is best displayed in The Origin of the Work of Art when Heidegger speaks of a painting by Van Gogh, which depicts some shoes. For Heidegger, the painting isn’t simply a representation of a pair of footwear. Rather:
From the dark opening of the worn insides of the shoes the toilsome tread of the worker stares forth. In the stiffly rugged heaviness of the shoes there is the accumulated tenacity of her slow trudge through the far-spreading and ever-uniform furrows of the field swept by a raw wind ... This equipment is pervaded by uncomplaining anxiety as to the certainty of bread, the wordless joy of having once more withstood want, the trembling before the impending childbed and shivering at the surrounding menace of death. This equipment belongs to the earth, and it is protected in the world of the peasant woman.