Your ordinary laboratory rat is no mean critic of art, if only properly cultivated. Teach him to discriminate a square from a rectangle and reward him for his appreciation of the latter and, very soon, he will become quite a connoisseur of rectangles, preferring rectangles with ever finer length-to-width ratios. In fact, the rat may be a more sophisticated critic than many of his human cousins. For whereas most people adopt an essentially pornographic approach to culture in assuming that art is the contemplation of beautiful and singular objects, the rat operates by principle and divines a rule (rectangularity) as the basis of his aesthetic.