Nozick's Experience Machine

Nozick's Experience Machine (or Pleasure Machine) is a theoretical machine, proposed by Robert Nozick as a thought experiment in Anarchy, State, and Utopia (New York: Basic Books, 1974), that exists exclusively to stimulate a human brain and its reward centres to produce consistently positive feelings, generating a pre-determined sequence of desired and pleasurable experiences in the mind, of such efficiency that the person using the N.E.M. is unable to distinguish between the machine-induced state and any external reality.

Nozick's thought experiment supposes that if the experience of pleasure is the essential value of being or the absolute good, as supposed by ethical hedonism, that there can be no serious objection to the exclusive use of the N.E.M., unless we accept that the experience of pleasure is not the essential value of being, thereby refuting ethical hedonism.