Reading medieval literature, it's hard not to be impressed with how much the characters get done--as when we read about King Harold doing battle in one of the Sagas of the Icelanders, written in about 1230. The first sentence bristles with purposeful action: "King Harold proclaimed a general levy, and gathered a fleet, summoning his forces far and wide through the land." By the end of the third paragraph, the king has launched his fleet against a rebel army, fought numerous battles involving "much slaughter in either host," bound up the wounds of his men, dispensed rewards to the loyal, and "was supreme over all Norway." What the saga doesn't tell us is how Harold felt about any of this, whether his drive to conquer was fueled by a tyrannical father's barely concealed contempt, or whether his legacy ultimately surpassed or fell short of his deepest hopes.
Physicists know how to use quantum theory--your phone and computer give plenty of evidence of that. But knowing how to use it is a far cry from fully understanding the world the theory describes--or even what the various mathematical devices scientists use in the theory are supposed to mean. One such mathematical object, whose status physicists have long debated, is known as the quantum state.
In A History of Reading, the Canadian novelist and essayist Alberto Manguel describes a remarkable transformation of human consciousness, which took place around the 10th century A.D.: the advent of silent reading. Human beings have been reading for thousands of years, but in antiquity, the normal thing was to read aloud. When Augustine (the future St. Augustine) went to see his teacher, Ambrose, in Milan, in 384 A.D., he was stunned to see him looking at a book and not saying anything.
Last January I was walking with my granddaughter along a beach near Melbourne when we noticed several people gathered around a rock pool, peering into the water. Wondering what had attracted their attention, we went over and saw that it was an octopus. If the spectators were interested in it, it also seemed interested in them. It came to the edge of the pool, one of its eyes directed at the people above, and stretched a tentacle out of the water, as if offering to shake hands. No one took up the offer but at least no one tried to capture the animal or turn it into calamari. That was pleasing because, as Peter Godfrey-Smith says in his recent book Other Minds: The Octopus, the Sea, and the Deep Origins of Consciousness, an octopus is "probably the closest we will come to meeting an intelligent alien."
In 2004 Peter König made a special belt: one that always vibrated on the side of it facing north. Put on the belt and face north, and it would vibrate in the front; turn to face west and it vibrated on the right side. König, a cognitive scientist at the University Osnabrück, Germany, gave it to a man named Udo Wächter to wear as part of a pilot study. After just six weeks, Wächter had developed an amazing and much-improved sense of direction. Even in a town 100 miles away, he could immediately point to his home.