Robert Nozick's Pleasure Machine and Why Almost Nobody Plugs In

On a few pages near the start of Anarchy, State, and Utopia (1974), Robert Nozick asks the reader to imagine a tank, a set of electrodes, and a team of neuropsychologists who can stimulate any experience you choose: writing the novel, falling in love, climbing the mountain. Once you are floating in the tank you will not know you are in it. Subjectively your life will be exactly the life you wanted. The deal is for life. Would you plug in?

Nozick's bet is that you would not. If pleasurable experience were all that mattered, the answer should be obvious: every minute outside the tank is a worse minute than every minute in it. Most readers refuse anyway, and Nozick lists three reasons. We want to actually do things, not merely have the experience of doing them. We want to be a certain kind of person — someone courageous, someone honest — and a body in a tank is, as he puts it, "an indeterminate blob." And we want some contact with a reality deeper than what is being piped into our cortex. The thought experiment was meant to refute hedonism in three sentences and it did.

It has had a long second life as data. In 2010 the philosopher Felipe De Brigard ran an empirical version. He told one group of subjects they were already plugged into the machine, then offered them the choice to disconnect into the real world. Only 46 percent said yes — and when subjects were told their real life was as a prisoner, just 13 percent wanted out. The result reframes Nozick's argument from a clean intuition into something messier: people refuse the machine partly because they prefer authentic reality, but also partly because they prefer the life they already have. Status quo bias does a lot of the work the philosophy was meant to do alone.