What do we really mean when we call something “ugly”? We tend to use the word to describe something that is somehow unappealing. Of course, there are plenty of ugly things: an ill-fitting suit, a drab new office building, a shopping cart dumped in a river. But when things are unpleasant because they’re ugly, it’s usually because they’re also boring or harmful; because they make us, and our environment, worse. This sort of “ugliness” is purely negative.

But just think of all the many wonderful things a different sort of ugliness—a more determined, more creative, more positive ugliness—can achieve.¹ From the grotesque and comic fusions of medieval marginalia, to the indignities perpetuated on the body in the paintings of Francis Bacon, and the auto-tuned frenzy of experi...