Nozick’s experience machine
Robert Nozick, Anarchy, State, and Utopia, chapter 3 · 1974
A machine that gives you any life you choose, one you can’t tell from the real thing. Would you plug in?
Suppose a machine could give you any experience you wanted. Neuropsychologists could stimulate your brain so you’d think and feel you were writing a great novel, making a friend, or reading an interesting book. All the while you’d be floating in a tank with electrodes attached to your brain. You can program your experiences for the next two years, then come up for ten minutes to pick the next two. Should you plug in for life?
Nozick thought most people would say no. Surveys since find the answers shift with how the case is framed, especially with whether you’re already plugged in (De Brigard, 2010). He drew three conclusions. We want to actually do certain things, not just have the experience of doing them. We want to be a certain kind of person, and a body floating in a tank is no kind of person. And we want contact with a reality deeper than anything we could construct. If experience were all that mattered, none of that would count. So experience isn’t all that matters.
The argument was aimed at hedonism and the simplest forms of utilitarianism, and it still has force. It also works as a design brief for a simulation: what would a world look like if it were built to be plugged into? The Afterlife preset answers that. It has a painted set, single player, nothing rendered unless you want it, suffering off, and time in a loop.
The sandbox works out how much computing that paradise takes, and the answer is telling. It’s among the cheapest builds available. No suffering means no stakes, no stakes means little to compute, and the total collapses. Three of the four schools in the ethics window object. The fourth endorses it, because a painless world of maximum bliss is what its arithmetic recommends.
There’s a second reading. Nozick asks whether you’d choose the machine. The simulation hypothesis asks whether you’re already in one and nobody asked you. His three reasons for refusing are the same three reasons a simulated person might feel wronged. None of them is about how good the rendering is.