The aim of landscape design is to make good outdoor places. A full appreciation of this point can be the starting point for a revival of landscape theory. But exponents of the art should work as practical philosophers, not philosopher-kings. Kingship is a dead idea from a bygone age. English landscape design developed within the Ideal Theory of Art. This derived from Aristotle's interpretation of Plato's Theory of Ideas. Just as one can read a novel from the viewpoints of literary style, philosophical outlook, characterization, narrative or social history, so one should be able to read a plan from the viewpoints of colour harmony, ornament, composition, proportion, social value, conservation value, symbolism, mythology, narrative. It is a layered approach to design, and it fits remarkably well with the layering capabilities of computer-aided design (CAD) and geographical information systems (GIS). Ideas, representable by patterns, should lie at the intellectual heart of landscape design and planning.