[7] I believe when a thing is once _well done_ in this world, it never can be done _over again_.
§ 1. We saw, in the course of the last chapter, with what kind of feeling an artist ought to regard the character of every object he undertakes to paint. The next question is, what objects he _ought_ to undertake to paint; how far he should be influenced by his feelings in the choice of subjects; and how far he should permit himself to alter, or, in the usual art language, improve, nature. For it has already been stated (Vol. III. Chap. III. § 21.), that all great art must be inventive; that is to say, its subject must be produced by the imagination. If so, then great landscape art cannot be a mere copy of any given scene; and we have now to inquire what else than this it may be.
§ 2. If the reader will glance over that twenty-first, and the following three paragraphs of the same chapter, he will see that we there divided art generally into "historical" and "poetical," or the art of relating facts simply, and facts imaginatively. Now, with respect to landscape, the historical art is simple topography, and the imaginative art is what I have in the heading of the present chapter called Turnerian topography, and must in the course of it endeavor to explain.
Observe, however, at the outset, that, touching the duty or fitness of altering nature at all, the quarrels which have so wofully divided the world of art are caused only by want of understanding this simplest of all canons,--"It is always wrong to draw what you don't see." This law is inviolable. But then, some people see only things that exist, and others see things that do not exist, or do not exist apparently. And if they really _see_ these non-apparent things, they are quite right to draw them; the only harm is when people try to draw non-apparent things, who _don't_ see them, but think they can calculate or compose into existence what is to them for evermore invisible. If some people really see angels where others see only empty space, let them paint the angels; only let not anybody else think _they_ can paint an angel, too, on any calculated principles of the angelic.
§ 3. If, therefore, when we go to a place, we see nothing else than is there, we are to paint nothing else, and to remain pure topographical or historical landscape painters. If, going to the place, we see something quite different from what is there, then we are to paint that--nay, we _must_ paint that, whether we will or not; it being, for us, the only reality we can get at. But let us beware of pretending to see this unreality if we do not.