What, if anything, makes life worth living? What matters to us most as human beings, and hence enables us to live the good life? Could it be knowledge, or worthwhile achievement, or love? Philosophers have produced various answers to this question. Aristotle argued that the good life is one lived according to reason, where we as rational beings exercise our rationality and virtue. Accordingly, we'd be in a state of flourishing. (Philosophers would apparently be living the ultimate form of life, on this view.) Alternatively, philosophers have come up with two main competing theories to Aristotles's: hedonism and objective-list theory. These two views contrast with each other really well. Hedonism says all that matters for a life to go well only has to do with having good experiences, namely, pleasure and happiness. Objective-list theory, on the other hand, moves right away from hedonism's first-person perspective, and says that all that matters is what can be “seen from the outside”, and from here we try to construct an open-ended list of all the things that are objectively valuable that can be plausibly said to make a life go well. Presumably, we'd include things on this list like knowledge, achievement of worthwhile ends, wisdom, friendship, and so on.
How are we to decide between these three views? One way may be to subject each view to criticism, and see which one fares best. So the objective-list theorist may say to the hedonist that hedonism can't be true because someone could conceivably get happiness counting blades of grass or from watching Nicolas Cage films. The hedonist may in turn say to the Aristotelian or the objective-lister that exercising one's rationality, or pursuing worthwhile ends, actually makes one miserable, and this is by no means a good life. Constantly exercising one's rationality may lead one to be constantly vigilant about one's moral obligations to humanity, and to be constantly weighed down by the knowledge of having done morally wrong things in the past, like dismissing the desperate needs of a friend.
Another way may be to say that one theory is getting at something of fundamental value, while the other two are getting things right, but are only describing things of value that are dependent or derivative of whatever it is that has fundamental value. On this pluralistic view, one possibility would be that pleasure is what primarily has importance for a life to go well, and flourishing and objective-list values are things that are valuable in virtue of enabling us to have a pleasurable and happy life.
Some philosophers have taken themselves to have demonstrated what it couldn't possibly be that makes life worth living. The best example of this can be found in Robert Nozick's influential book Anarchy, State, and Utopia (AS&U, 1974, pp. 42-45). The book itself is a sustained criticism of John Rawls' masterwork A Theory of Justice (1971), where we find in Nozick's book a mere four paragraphs that appear to be a digression within a digression, but has turned out to be the most widely read and reproduced part of AS&U. Nozick constructs a thought experiment of the experience machine in order to refute hedonism:
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's experiences?… Of course, while in the tank, you won't know that you're there; you'll think it's all actually happening. . . . Would you plug in? What else can matter to us, other than how our lives feel from the inside?
What does matter to us in addition to our experiences? First, we want to do certain things, and not just have the experience of doing them. In the case of certain experiences, it is only because first we want to do the actions that we want the experiences of doing them or thinking we've done them. (But why do we want to do the activities rather than merely to experience them?) A second reason for not plugging in is that we want to be a certain way, to be a certain sort of person. Someone floating in a tank is an indeterminate blob. There is no answer to the question of what a person is like who has long been in the tank. Is he courageous, kind, intelligent, witty, loving? It's not merely that its difficult to tell; there's no way he is. Plugging into the machine is a kind of suicide. It will seem to some, trapped by a picture, that nothing about what we are like can matter except as it gets reflected in our experiences. But should it be surprising that what we are is important to us? Why should we be concerned only with how our time is filled, but not with what we are?
We learn that something matters to us in addition to experience by imagining an experience machine and then realizing that we would not use it.
Nozick here takes the putative fact that we would choose to not plug in to the experience as a refutation against hedonism. What else can matter to us, other than how our lives feel from the inside? The hedonist is committed to the only thing mattering to us being precisely this, so it would be devastating news for hedonism if the experience machine thought experiment elicited reliable judgments that plugging into a life of bliss would be the wrong thing to do.
Nozick has certainly given a compelling challenge to the hedonist, so it's up to the hedonist to show why Nozick's famous brain-in-a-vat style thought experiment is defective or preventing us from producing reliable judgments. The first thing would be for the hedonist to question Nozick's framing of the thought experiment. Firstly, in the normal, unenvatted case, Nozick seems to be presupposing that we have direct contact to reality. And perhaps this then leads him to locate the mind and self in a particular conception of reality, and to stipulate that when you're envatted, you only have a pseudomind and a pseudoself. (“Someone floating in a tank is an indeterminate blob.” So what happened to all their blissful experiences?) Thirdly, even if the virtual reality we plug into is second-rate in some sense, why couldn't we still have a certain character and be a certain way, contrary to what Nozick says?
It seems to me that each of the points doing the work in Nozick's thought experiment can all be answered by the hedonist, and in turn, the hedonist can construct an experience thought experiment of her own for which most of us would judge reliably that we ought to plug into.
The first thing we need to overcome is the initial yuck response that we get from the thought of being a body or a brain floating in a vat. Perhaps it's worth changing things to a Matrix style setup where we recline and plugin. That's already much better than the thought of floating unconsciously. Secondly, let's get away from the classic brain-in-a-vat scenario where the world for the envatted person is wholly constituted by the person's mind. Let's stipulate that the experience machine we're plugging into is a computer simulation of all of physics. As the Australian philosopher David Chalmers argues, it's possible that such a situation actually preserves many structures of reality, so the virtual reality of the experience machine is by no means to be second-rate (in a metaphysical sense, rather than in the perceivable sense). Furthermore, it seems to me that views such as Nozick's that say that the person plugged into the experience machine is getting things systematically wrong—the traditional sceptical interpretation of the brain-in-a-vat, in other words, where all of your beliefs turn out to be false—can in an important sense equally be applied to us unenvatted people. Why not say that our beliefs about the world are systematically false, given that what our perceptual experience tells us is radically different to what we get from fundamental physics? The problem with this kind of view, as I've argued before, is that it illegitimately gives privilege to one perspective among many that have equal claim to giving us accurate representations of the world. Therefore, it seems to me that there is a strong argument that Nozick himself is committed to a view human minds being reduced away to “atoms in the void.”
The final criticism of Nozick is his view that we have direct access to reality. It seems to me that philosophers in the empiricist tradition (with John McDowell being a notable but obscure exception) have proven the direct access view to be false. Our contact with reality is always mediated by representation in a very strong sense. There is a strong barrier of perceptual experience and interpretation between us and reality. Our brains are literally experience machines that construct the virtual realities that we live in.
So hopefully at this stage I've cleared enough ground for the hedonist to construct an experience machine thought experiment of her own, and furthermore, one in which we'd all strongly assent to plugging into. Let's begin with a scenario on Earth where every human being can plug into the experience machine. This avoids the objection that we don't want to leave behind those we love. We've taken steps to ensure the wellbeing of the animals and the environment that we leave behind. We can all go to a place where we can recline and relax while we plug into the experience machine. The experience machine simulates all of physics, so our minds are physically realised in a level of reality equally as it's physically realised in a level reality in the original world. We all plug into a world that is at once very familiar but very different. We find ourselves with bodies and minds, in a similar world of concrete objects. However, some things are different. There's no serious competition for resources nor any serious conflict of desires. There is no suffering. There are many explanations for this. One explanation could be that our brains have different default networks, which has been thought to be responsible for many of the negative thoughts that we spontaneously have when we go about our daily routines. It's very likely that our default networks were extremely useful in the pleistocene, where we faced great social and environmental dangers, but it seems to be maladapted to our modern worlds. In short, the experience machine would provide us with a heaven we could get to (not that we'd want to live immortal lives at all); a place where we could be with the people we love and pursue our projects without living in a world where children are dying of famine and warfare, where there are no global corporations polluting the environment, and we don't have to worry about paying the mortgage.
This thought experiment is far away from Nozick's, and it may be objected that I'm helping myself to too much, but this scenario is essentially an experience machine thought experiment at the end of the day, and that's all I need to vindicate the hedonist. This experience machine also has benefits that aren't strictly within the hedonistic paradigm. For example, when the Ancient Greeks would ponder over the good life, they would consider what extent are lives are determined by chance, which it seems to me is something often missing from contemporary discussions. Chance and contingency is a hidden source of injustice in our world. It's purely by chance that I happened to be born in Adelaide, which is one of the safest places to live in the world. Equally, it's purely a contingency that someone may lose the love of their life only a few years after meeting each other, reducing the meaning that find in the world. The experience machine does away with these sorts of contingencies, while retaining pseudocontingencies that make life exciting and filled with happy coincidences.
What moral should we draw from these considerations? It's certainly not that we should hold our breath for an actual experience machine—although you'd no doubt would jump at the opportunity to plug in having read this essay. I think the conclusion we could safely draw is that, contrary to Nozick, the experience machine actually lends some support to hedonism. Therefore, we could justifiably say that the hedonist has discovered something of fundamental value, and the Aristotelian and the objective-lister have only discovered things of derivative value.