Experience machine

The Experience Machine or Pleasure Machine is a thought experiment put forward by philosopher Robert Nozick in his 1974 book Anarchy, State, and Utopia. It is one of the best known attempts to refute ethical hedonism, and does so by imagining a choice between everyday reality and an apparently preferable simulated reality.

If the primary thesis of hedonism is that "pleasure is the good", then any component of life that is not pleasurable does nothing directly to increase one's well-being. This is a view held by many value theorists, but most famously by some classical utilitarians. Nozick attacks the thesis by means of a thought experiment. If he can show that there is something other than pleasure that has value and thereby increases our well-being, then hedonism is defeated.

Nozick asks us to imagine a machine that could give us whatever desirable or pleasurable experiences we could want. Psychologists have figured out a way to stimulate a person's brain to induce pleasurable experiences that the subject could not distinguish from those he would have apart from the machine. He then asks, if given the choice, would we prefer the machine to real life?

Nozick also believes that if pleasure were the only intrinsic value, people would have an overriding reason to be hooked up to an "experience machine," which would produce favorable sensations.

Who would run the machines if everyone plugs in? Nozick asks us to ignore this concern, since it does not adversely affect the thought experiment. One could simply stipulate that the machines have been so well designed as to be fail-proof.

The experiment is also open to multiple interpretations. For instance, Nozick claims that you could either map out the rest of your life in the machine before plugging in, or you could unplug periodically to choose your programming for the next cycle. While interesting, these variations do not directly affect the argument.

The argument is along these lines:

Nozick provides us with three reasons not to plug into the machine.

Psychologist Joshua Greene says that our intuitions about the experience machine may be affected by status quo bias, and suggests reformulating the thought experiment in a form which counters this. According to his version:

...
Wikipedia