Hedonism is the philosophy that pleasure is the most important pursuit of mankind. The basic idea behind hedonistic thought is that pleasure is the only thing that is good for a person. This is often used as a justification for evaluating actions in terms of how much pleasure and how little pain (i.e. suffering) they produce. In very simple terms, a hedonist strives to maximize this total (pleasure minus pain).
The Experience Machine is a short section of Anarchy, State, and Utopia published by Harvard University philosopher Robert Nozick. The text is one of the best known attempts at a refutation of ethical hedonism.
If the primary thesis of hedonism is: "Pleasure is the good", then any component of life that is not pleasurable does nothing to increase one's well-being. This is a view held by many value theorists, but most famously by certain classical Utilitarians. Nozick seeks to attack hedonism by means of a thought experiment. If he can prove that there is something other than pleasure that has value to us and affects our well-being, then hedonism can be seen to be defeated.
The thought experiment
Nozick asks us to imagine an experience machine that could give us whatever desirable or pleasurable experiences that we could possibly want.
"Suppose there were an experience machine that would give you any experience you desired. Superduper neuropsychologists could stimulate your brain so that you would think and feel you were writing a great novel, or making a friend, or reading an interesting book. All the time you would be floating in a tank, with electrodes attached to your brain. Should you plug into this machine for life, preprogramming your life experiences? Of course, while in the tank you won't know that you're there; you'll think that it's all actually happening. Would you plug in?"
Nozick attempts to quell our initial concerns by shrugging them off on the basis of the intelligence of the experience machine scientists. For instance, a primary worry would be something like: who would run the machines if everyone plugs in? Nozick asks us to ignore these concerns, as they do not adversely affect the thought experiment.
The experiment is actually open to multiple interpretations. For instance, Nozick himself claims that you could either map out the rest of your life in the machine before plugging in, or you could go in and then step out for ten minutes every two years or so to choose your programming for the next cycle. While these different takes on the experiment are interesting, they do not directly affect the argument.
The argument runs somewhat along these lines:
P1: Hedonism means that the only thing that affects our well-being is pleasure
P2: If hedonism were correct, then we would plug into the machine because we would want pleasurable experiences
P3: We would not plug into the machine because we are concerned about the reality of our experiences
C: Therefore, there is something other than pleasure that affects our well-being and hedonism is therefore defeated.
Reasons to not plug in
Nozick provides us with three reasons not to plug into the machine:
We want to do certain things, and not just have the experience of doing them.
"It is only because we first want to do the actions that we want the experiences of doing them." (Nozick)
We want to be a certain sort of person.
"Someone floating in a tank is an indeterminate blob." (Nozick)
Plugging into an experience machine limits us to a man-made reality (it limits us to what we can make).
"There is no actual contact with any deeper reality, though the experience of it can be simulated." (Nozick)
Nozick firmly believes that there are components of our lives that matter to our well-being in addition to our experiences. We can learn this, he claims, simply by imagining the machine, and then deciding that we would not use it. If this is true, then, Nozick claims hedonism is defeated.