“Suppose there was 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? If you are worried about missing out on desirable experiences we can suppose that business enterprises have researched thoroughly the lives of many others. You can pick and choose from their large library or smorgasbord of such experiences, selecting your life’s experiences of, say, the next two years. After two years have passed, you will have ten minutes or ten hours out of the tank to select the experiences of your next two years. Of course, while in the tank you won’t know that you’re there; you’ll think that it’s all actually happening. Others can also plug in to have the experiences they want, so there’s no need to stay unplugged to serve them. (Ignore problems such as who will service the machines if everyone plugs in.) Would you plug in? What else can matter to us, other than how our lives feel from the inside?”

Nozick gives three answers:

We want to do certain things, rather than just have the experience of doing them. (But even Nozick asks, but why?) We want to be a certain way, to be a certain person. If we plug in, we’re just an “indeterminate blob.” Nozick asks, is the person in the tank courageous, kind, intelligent, witty, loving? How could we know? How could they be? Plugging in “limits us to a man-made reality, to a world no deeper or more important than that which people can construct. There is no actual contact with any deeper reality, though the experience of it can be simulated.”

The experience machine has created a whole literature, not to mention any number of sci-fi films. People have worked out variants, for example where you never emerge from the machine until your biological death, in order to get rid of the idea that you could ever become conscious of spending a lot of time just being a body in a tank, and so on.

People argue over whether Nozick got the right reasons to reject the machine. Some people may also take pleasure in the intellectual bravado of saying that they would plug in, that they see no reasons not to. That would be a typically annoying undergraduate posture to take up. (I’d know, I did for a whole afternoon. It was many years ago.)

The ongoing discussion just shows how great a concept the experience machine is. But the rejection of it, for most people who aren’t undergraduates in philosophy, is immediate and from the gut. (Not every belief or conviction that is instinctive and intuitive is necessarily right, though this one is.)

Experience machines exist, of course, and many of us plug ourselves in quite willingly. Some of those superduper people, for example, can help us flood our brains with a bitter, white crystalline purine, a methylxanthine alkaloid that is chemically related to the adenine and guanine bases of deoxyribonucleic acid and ribonucleic acid. This blocks the action of adenosine on its receptor in the brain and stimulates the autonomic nervous system. It makes us less drowsy, more alert, physically faster and better co-ordinated. It can increase our heart rate and pulse. You’ll be aware of course, that we don’t have to plug into electrodes and float in a tank for this. And the superduper people aren’t neuropsychologists, but more likely baristas. This experience machine is just a regular cup of coffee.

But physical symptoms and mental states are a two-way street. Research has shown, for example, that, even when you feel you have no reasons to, you can smile for a while and your mood will improve, or you can clench your fist for a while and that can make you more aggressive. And so this experience machine can give us the impression that we’re well rested and refreshed (not in any way drowsy or tired) or that we’re facing an amazing, interesting experience (alertness, fast pulse) or a fight-or-flight type situation (heart beating faster, sudden alertness) even when it’s just a routine Monday morning and we’re on our way to the day-job.

There is, of course, also the type of organic compound in which the hydroxyl functional group is bound to a saturated carbon atom. This is an experience machine that can give us the desirable experience of being socially less inhibited, much more certain that other people find us entertaining and generally convinced that we’re all round great people. It can be ingested in pleasant-tasting drinks like wine and beer.

And anyone who has ever seen a small child on a sugar rush may also find it easy to believe that sugar provides a desirable experience of enjoyment and mental energy, not least by activating dopamine in the brain in a way that is similar to stronger drugs.

I’ll call things like coffee or alcohol “mini experience machines.” After all, the effect lasts a much shorter time than a session in the superduper neuropsychologists’ floatation tank experience would. And it gives us not so much a whole set of new experiences that are wholly separate to what we’re doing and who we are, but it puts a little layer of, say, additional (alternative) reality, over and above that reality.

I’m not saying that coffee, alcohol and sugar are therefore bad things or that we need to reject them with the instinctive vehemence with which we would reject the idea of plugging into an experience machine. But it probably helps to be aware of the “experience machine light” effect of such things.

I also find some of the tools some of us work with are a bit like experience machines in that they give us an interface to interact with the world in a way that, as much as possible, reduces reality to things that pop up on a screen. So I know that people want to give me some information or want me to do something in something like the following way (that’s not my real inbox, by the way):

I can have conversations and exchanges with lots of people and all the while I’m just “plugged in” to a screen.

So, in fact, there may be lots of mini experience machines that interact in various ways to put layers of differing experiences across “real” life on a day-by-day basis. And although we may not have the same reasons to reject these mini experience machines – after all, they are more time-limited, localised in terms of their effect and less intrusive in the way we can link up to them – maybe we should aim to be suspicious of them, particularly if we’re veering to more extended use (both in terms of timing or in terms of range of experience), so if one or more of the following are true:

We use them in high doses, frequently or on a daily basis. They give us experiences that we worry we wouldn’t otherwise have enough of in our lives – excitement, connection, attention, confidence, mental energy. We would be forced to live our lives differently, if we didn’t have them. We couldn’t function properly in our daily lives without them.

But since I’ve declared so many things mini experience machines, would we even know whether we’re using them too much?

First of all, it is possible to take stock of the mini experience machines we use. We can then try not using them. Or, if that is too difficult, we could ask, what would the consequence be for the way I live my life, if I didn’t plug into this experience machine? How would I have to deal with the tiredness or the lack of challenges in my reality if I didn’t have coffee to simulate alertness? Why am I so inhibited when meeting people that I need alcohol to have its effect? What energy rush or feelings of enjoyment would I like that I currently take from sugar rushes?

And presumably, finding out about these things is what lots of people do these days when they sit down and pay attention to their breathing, to their mind and their thoughts with minimal stimulation from mini experience machines or communication technologies (particularly first thing in the morning when the body has processed all the ingested experience machines from the previous day). Maybe then they can listen to the real experience and find out if the like it, or not.

Or it may be away from screens in green spaces and in nature surrounded by other life forms who are less prone to plug into experience machines. Or it may be something we do while deeply involved in community, voluntary or religious activities. (These practices, by the way, have all been demonstrated to increase wellbeing.) They may also all help us to access the things in Nozick’s three reasons for rejecting experience machines: