And that was how I came to spend the entire main course recounting my two Ecba dialogs with Orolo: the first about how, according to him, consciousness was all about the rapid and fluent creation of counterfactual worlds inside the brain, and the second in which he argued that this was not merely possible, not merely plausible, but in fact easy, if one thought of consciousness as spanning an ensemble of slightly different versions of the brain, each keeping track of a slightly different cosmos. Paphlagon ended up saying it better: “If hemn space is the landscape, and one cosmos is a single geometric point in it, then a given consciousness is a spot of light moving, like a searchlight beam, over that landscape—brightly illuminating a set of points—of cosmi—that are close together, with a penumbra that rapidly feathers away to darkness at the edges. In the bright center of the beam, crosstalk occurs among many variants of the brain. Fewer contributions come in from the half-lit periphery, and none from the shadows beyond.”

Neal Stephenson, Anathem