Libet’s findings have been hard to replicate (zapping a patient’s exposed brain is frowned upon these days), and they remain controversial. But to Eagleman they make a good deal of sense. Like Kublai Khan, he says, the brain needs time to get its story straight. It gathers up all the evidence of our senses, and only then reveals it to us.
He had spent the past ten years peering at the world through such gaps in our perception, he said. “But sometimes you get so far down deep into reality that you want to pull back. Sometimes, in a great while, I’ll think, What if I find out that this is all an illusion?” He felt this most keenly with his schizophrenic subjects, who tended to do poorly on timing tests. The voices in their heads, he suspected, were no different from anyone else’s internal monologues; their brains just processed them a little out of sequence, so that the thoughts seemed to belong to someone else. “All it takes is this tiny tweak in the brain, this tiny change in perception,” he said, “and what you see as real isn’t real to anyone else.”