In Isaac Newton's lifetime, no more than a few thousand people had any idea what he looked like, though he was one of England's most famous men, yet now millions of people have quite a clear idea—based on replicas of copies of rather poorly painted portraits. Even more pervasive and indelible are the smile of Mona Lisa, The Scream of Edvard Munch, and the silhouettes of various fiction extraterrestrials. These are memes, living a life of their own, independent of any physical reality. "This may not be what George Washington looked like then," a tour guide was overheard saying of the Gilbert Stuart painting at the Metropolitan Museum of Art, "but this is what he looks like now." Exactly.

For this bodiless replicator itself, Dawkins proposed a name. He called it the meme, and it became his most memorable invention, far more influential than his selfish genes or his later proselytizing against religiosity. "Memes propagate themselves in the meme pool by leaping from brain to brain via a process which, in the broad sense, can be called imitation," he wrote. They compete with one another for limited resources: brink time or bandwidth. They comet most of all for attention.

"Time flows on, never comes back," said Leon Brillouin in 1949. "When the physicist is confronted with this fact he is greatly disturbed."

A stranger is at a party of people who know one another well. One says, "72," and everyone laughs. Another says,"29," and the party roars. The stranger asks what us going on. His neighbor said,"We have many jokes and we have told them so often that now we just use a number." The guest thought he'd try it, and after a few words said,"63." The response was feeble. "What's the matter, isn't this a joke?" "Oh, yes, that is one of our very best jokes, but you did not tell it well."

In more ways than one, using the telegraph meant writing in code. The Morse system of dots and dashes was not called a code at first. It was just called an alphabet: "the Morse Telegraphic Alphabet," typically. But it was not an alphabet. It did not represent sounds by signs. The Morse scheme took the alphabet as a starting point and leveraged it, by substitution, replacing signs with new signs. It was a meta-alphabet, an alphabet once removed.

The composer John Cage, who had a lifelong interest in silence, used to tell a story about an event that depended his understanding of what silence meant. In 1952 he heard that acoustical engineers at Harvard had created a completely soundproof room, an anechoic chamber, and he arranged to spend some time in it. When he emerged, he told the technicians that it didn't work: he could hear two noises, one low and one high. "Oh," they said, "everyone hears those—the low hum is your circulating blood, the high whine is your nervous system."

And the reflection...well, I guess the reflection represents art. It's what lies between our dreams and reality.

White feigned neutrality, but it was loaded with meaning.

It was impossible to know if this new art was good, because, mostly, good art had been defined by its endurance over time.