And it’s true that the way we see the world is riven through with untested, unverifiable assumptions about what it means to have a self. It’s true that we might possess no will of our own, just be acting out determined or random steps and dreaming of choice-making; that we could be brains in jars, or surgical patients on operating tables or old women dying alone in nursing homes fantasising about other lives, or alien players of immersive games trapped in the system, or even just simulations of simulations in some enormous engine analysing a stock market in a universe far above our own; or that we might be physically real, but exist in fact as a sequence of selves, each alive only for an instant in the uptick of an electrical pulse, gone again the next, each fraudulently recollecting in his own short span the chemically stored memories of a billion others back down the line to the womb and declaring them his own. And that’s just how we fail to understand ourselves, before we even touch the mystery that is other people. Do they think at all? Do they think the same way that we do? Do they experience love, hope, self? Or do they merely behave as if they do? We have no way of knowing—not yet, not until we can connect two heads with thick, ropy cables and taste with another person’s tongue, share the feeling of wine or wind on their lips. Even then, consciousness regresses, an endless loop of doubt.