Never. It requires that we willfully accept ignorance.
Source: the character Cypher from the movie The Matrix, a troubled, weak individual who prefers the ignorance of a "blissful" life in the Matrix as opposed to confronting his problems and improving the real world.
Epicurus argues against UNNATURAL desires. Such things, though they might be saturated with pleasure, can lead to pain. This machine idea seems to be the ultimate theoretical unnatural construct. It’s a “gotcha” trap…
Instead of a machine it could be a “pleasure drug” that comes in pill form.
A pleasure machine doesn’t exist naturally, it must be made to be manifested into reality. So it already is outside of natural processes that lead to pleasure. Everything has consequences, actions and reactions in reality. So a thought experiment where there are no consequences based on observable experiences isn’t reality and is now beyond the scope of Epicurean philosophy. This line of abstract argument is for adversarial Idealist philosophers attempting to trap Epicureans…the answer for the Epicurean is don’t play the game and don’t step into the idealist arena because THAT isn’t real. The world of the pleasure machine doesn’t exist, just like the the world of pink fluffy invisible dragons that grant wishes doesn’t.
There are many unnatural unnecessary things we might desire…people say that heroin feels like the greatest pleasure, but we all know what happens when someone goes down that road. Consequences. Consequences in reality. And since hooking yourself up to a “pleasure machine” in reality must also like heroin have consequences then we must accept this machine is an UNNATURAL and UNNECESSARY desire that will lead to pain. Given the testable and observable evidence for people who have addictions to the cyber world: VR, social media, pornography, video game addiction, there is very good evidence that this machine idea is a red herring.
I just feel like this hypothetical is in the realm of it being entirely implausible given the particular parameters. Its an idealist abstraction that doesn’t take into account reality. How reality works, how nature works, how human behavior works.
To argue against this you’d need far more detail, by the person positing this absurdity. So is this universe one where humans don’t need social interaction? Need to have sex? Need to reproduce? Need to eat? Need to work? Need to exercise? Are the effects of the machine identical to actual tactile experiences in reality? Is the effect on the brain the same? If the idea is just being posited in a vacuum then no, this question is an absurdity because it refuses to take into account reality and it’s akin to any idealist abstract hypothetical. It’s a trap…
Saying this hypothetical machine exists, it has to exist in the same universe where the natural pleasures ALSO exist, otherwise by what standard would the machine or person judge what a perfect “artificial” copy version of the pleasure is? Without the natural version as a standard? Then the person could judge whether the real thing is better. This universe is a necessity for the machine to exist. In a universe where pain is also present to contrast with pleasure. So it cannot just exist hypothetically in a paradise-like vacuum where there are no problems or pain humans experience on the regular…that would necessitate a “magical” pleasure machine to escape them. And if it does exist here the parameters must change.
It can’t be both ways for the person positing this… it has to exist in this natural universe and if it does it has to operate exactly how nature operates here. Otherwise we might as well be talking about how many feathers are on Cherubim wings as opposed to Seraphim wings….or if two headed dragons are more likely to live in mountain caves as opposed to underground caves.
Your argument seems to be "but it wouldn't be pleasurable because A, B, C" which is avoiding the thought experiment which states that using the machine is IN FACT more pleasurable than not doing so.
Nah, I wouldn't say that it wouldn't be pleasurable, but I did avoid the question, that's true 
Further there is empirical evidence against Nozick at this time since VR headsets now exist and are being used by people. Most people who use VR headsets would not think "but the things in the game are not REAL" or "you could do other things with your time" are valid arguments against using them. They use the headsets because they like it and that is all the justification needed.
That's a very good point, which invalidates the whole augment of Nozick! Thank you, I didn't even thought about that for one second, but you're right!
if we accept that parameters of the thought experiment as given, that using the machine
The parameters don't seem so cut and dried. Here is Nozick's excerpt: https://rintintin.colorado.edu/~vancecd/phil3160/Nozick1.pdf
I haven't had a chance to read the paper yet but am putting it here for reference.
I hadn't either, but I did now, so thank you.
I still get the impression that he intends to convey that the experiences in the experience machine would in fact be highly pleasurable from the point of view of the person in the machine. The reason you are expected to not want to go in the machine is that you would end up being deceived, and live a fake life.
A couple points relevant to the current discussion, from the later source, The Examined Life (1989):
The question is not whether to try the machine temporarily, but whether to enter it for the rest of your life
would seem to weaken the VR headset counterargument.
Notice that this is a thought experiment, designed to isolate one question: Do only our internal feelings matter to us? It would miss the point, then, to focus upon whether such a machine is technologically feasible.
one might of course insist that thought experiments that are counterfactual to physics are invalid (is this one? I can't tell), but the premise is clearly that the machine does exist.
Readers who hold they would plug in to the machine should notice whether their first impulse was not to do so, followed later by the thought that since only experiences could matter, the machine would be all right after all.
I can be an adherent to a particular philosophy yet not be practiced enough / have phronesis / be sage enough that my fist impulse is the correct one or the one I end up following. But is this really ethically relevant? This reads a bit like shaming people out of the machine.
Few of us really think that only a person’s experiences matter. We would not wish for our children a life of great satisfactions that all depended upon deceptions they would never detect: although they take pride in artistic accomplishments, the critics and their friends too are just pretending to admire their work yet snicker behind their backs; the apparently faithful mate carries on secret love affairs; their apparently loving children really detest them; and so on. Few of us upon hearing this description would exclaim, “What a wonderful life! It feels so happy and pleasurable from the inside.”
I was amused that Nozick did in fact use a similar cheating wife argument. I would say about the life described in the quote that it seems easier to say "what a pleasurable life!" than "what a happy life!". Provided of course that the person does in fact not detect the deceptions.
I would guess (but I do not know since I'm not well-read enough) that it is significant that Epicurus bases value on pleasure rather than happiness. Pleasure is a direct experience, it is not possible to be deceived about whether you are feeling pleasure. On the other hand happiness is a very difficult and hard to pin down concept. Apparently Aristotle thought you could become unhappy even after your death if for example all your children die after you died.
Of course we wish people to have many such moments and days of happiness.... Yet it is not clear that we want those moments constantly or want our lives to consist wholly and only of them. We want to experience other feelings too, ones with valuable aspects that happiness does not possess as strongly. And even the very feelings of happiness may want to direct themselves into other activities, such as helping others or artistic work, which then involve the predominance of different feelings. We want experiences, fitting ones, of profound connection with others, of deep understanding of natural phenomena, of love, of being profoundly moved by music or tragedy, or doing something new and innovative, experiences very different from the bounce and rosiness of the happy moments. What we want, in short, is a life and a self that happiness is a fitting response to—and then to give it that response.
And would not the above quote seem rather silly if we replace "happiness" with "pleasure"? I read the above as saying that the problem with happiness is that it is only part of a pleasurable life. Which is probably true, but it is not an argument against pleasure as being the basis of value.
e: do tell me if I'm wildly off base here, this is something I've been thinking about for a bit so I wanted to jump into the discussion.
I think in general a "feeling of happiness" because it is a feeling is well within the category of pleasure. It's when people start to embellish "happy" with all sorts of other definitions that are not feelings that the problem comes.
I just feel like this hypothetical is in the realm of it being entirely implausible given the particular parameters. Its an idealist abstraction that doesn’t take into account reality. How reality works, how nature works, how human behavior works.
And I think you are describing Platonism / Stoicism / virtue exactly: "idealist abstraction that doesn't take into account reality, how reality works, etc.
