For first of all we must prepare a Natural and Experimental History, sufficient and good; and this is the foundation of all; for we are not to imagine or suppose, but to discover, what nature does or may be made to do.
An illustrational form tells you through the intelligence immediately what the form is about, whereas a non-illustrational form works first upon sensation and then slowly leaks back into the fact.
Painting is a duality and abstract painting is an entirely aesthetic thing. It always remains on one level. It is only really interesting in the beauty of its patterns or its shapes.