Except that it did not in this case. When Richard closed his eyes again to towel his face, he could still see a little patch of nothing in his visual field. This was a different sort of nothing from the field of red-tinged black that his eyes were seeing simply by virtue of the fact that his lids had closed over them. He knew what this was. The flash of reflected sun, a minute ago, had triggered a thing in his brain called an optical migraine. It was painless and harmless. He got them a few times a year. It was a visual display—“Aura”—caused by a temporary disruption of blood flow to the visual cortex. It always started thus, with a tiny dazzled region that refused to go away. Over the next half hour it would get bigger, making it impossible for him to read. Then it would gradually migrate rightward and mess with his peripheral vision on that side for a little while before disappearing without a trace.

The affected region—the spot where he was absolutely blind—was not black, as you might imagine. This could be proved simply by closing his eyes so that he actually was seeing just black. The blind spot then showed up as a region of vaguely defined yellow and black stripes, like the patterns painted on factory floors to limn danger zones, except that these flashed and fluctuated like an old-time television with its vertical hold out of whack.

Even as he drew these connections he was erecting defenses against a likely flanking attack from Polycultia, one of the Furious Muses, who was always pointing out that everything Richard could possibly think of was culturally relative. In this instance she might expect tactical support from Cerebra, an unintentionally offensive FM who had a knack for pointing out that any idea Richard came up with that he thought was clever was, in fact, but an imperfect rendering of a smarter idea that had occurred to her a long time ago. The projected line of attack from the Polycultia–Cerebra axis went something like this: Okay, because part of Richard’s visual cortex was on the blink, he was seeing “nothing” in that region. His brain was in the business of constructing, from moment to moment, the sort of three-dimensional model of the universe that, for example, enabled him to grab his phone from his bedside table without opening his eyes. As such, it couldn’t tolerate seeing a patch of “nothing” in the middle of an otherwise coherent reality. So it tried to fill in the nothing with something. It was simply the visual equivalent of tinnitus.