Science had taught him to be skeptical of cosmic certainties, [Eagleman] told me. From the unfathomed complexity of brain tissue—”essentially an alien computational material”—to the mystery of dark matter, we know too little about our own minds and the universe around us to insist on strict atheism, he said. “And we know far too much to commit to a particular religious story.” Why not revel in the alternatives? Why not imagine ourselves, as he did in Sum, as bits of networked hardware in a cosmic program, or as particles of some celestial organism, or any of a thousand other possibilities, and then test those ideas against the available evidence? “Part of the scientific temperament is this tolerance for holding multiple hypotheses in mind at the same time,” he said. “As Voltaire said, uncertainty is an uncomfortable position. But certainty is an absurd one.”