Attempts to create reality as we imagine it run up against the physical world. This serves as both an inhibition and a safeguard, as with destructive political and social aims. Only artists (in any medium) can conceive and make conception real, through putting imagination into craft. They are limited only by their imagination, and their skill. But these once again depend on the realities of the physical world: what artists can manage, and what they have experienced.
Art which does not reflect the world of sense experience—in recombination and analogy, for art need not and perhaps should not be literal and strict in its reflection—appears abstract, internal, surreal, dreamlike, or else rings false, hollow, or botched in attempts at concreteness.
The problem would seem to be that of an excessive internalism, either ignoring sense phenomena in favor of an internal symbolic reality, or parodying sense phenomena in abstracted form. This art may be great in its own world or by its own definition, but it is not art that can legislate for ours, as Percy Bysshe Shelley proposed of poets; artists who do not experience and render painstaking truth with their dreams cannot serve as Solons—Solons for the spirit, not the law. In fact they are ever more subject to suffering under the impositions of reality, except insofar as they are able to escape it momentarily in the process of creation.