“Many textbooks point out that no animal has evolved wheels and cite the fact as an example of how evolution is often incapable of finding the optimal solution to an engineering problem. But it is not a good example at all. Even if nature could have evolved a moose on wheels, it surely would have opted not to. Wheels are good only in a world with roads and rails. They bog down in any terrain that is soft, slippery, steep, or uneven. Legs are better. Wheels have to roll along an unbroken supporting ridge, but legs can be placed on a series of separate footholds, an extreme example being a ladder. Legs can also be placed to minimize lurching and to step over obstacles. Even today, when it seems as if the world has become a parking lot, only about half of the earth's land is accessible to vehicles with wheels or tracks, but most of the earth's land is accessible to vehicles with feet: animals, the vehicles designed by natural selection.”

“Many artists and scholars have pointed out that ultimately art depends on human nature.”

“There is no society ever discovered in the remotest corner of the world that has not had something that we would consider the arts. Visual arts - decoration of surfaces and bodies - appears to be a human universal.”

“Art works because it appeals to certain faculties of the mind. Music depends on details of the auditory system, painting and sculpture on the visual system. Poetry and literature depend on language.”

“The decline of violence isn't a steady inclined plane from an original state of maximal and universal bloodshed. Technology, ideology, and social and cultural changes periodically throw out new forms of violence for humanity to contend with.”

“Technology, ideology, and social and cultural changes periodically throw out new forms of violence for humanity to contend with.”

“Reading is a technology for perspective-taking. When someone else's thoughts are in your head, you are observing the world from that person's vantage point.”

“The rules of friendship are tacit, unconscious; they are not rational. In business, though, you have to think rationally.”

“The art of photography is all about directing the attention of the viewer.”

“America had, for one thing, lived in anarchy for - until much more recently than Europe. We had the Wild West, where the cliche of the cowboy movies was the nearest sheriff is 90 miles away, and so you had to pack a gun and defend yourself.”

“Though knowledge itself increasingly ignores boundaries between fields, professors are apt to organize their pedagogy around the methods and history of their academic subculture rather than some coherent topic in the world.”