I’m one of those 40 million Americans who struggle with insomnia. And so I’m here today with an insomniac question: Why can falling asleep be so difficult?

There has been an exciting surge of research about sleep over the past twenty years. It is described very clearly byMatthew Walker—professor of neuroscience and psychology at UC Berkeley—in his 2017 bookWhy We Sleep. He identifies a variety of culprits that are now known to contribute to rampant sleep deprivation in the U.S. among insomniacs and others. They include: light from personal electronics; rigid and demanding work and school schedules; alcohol consumption; and the misconception that sleeping pills induce natural sleep.

All of this data is illuminating, and Walker’s book is well worth the read. But here I’m not looking for a third-personal story of the causal factors that adversely affect sleep. I’m asking a slightly different question: what explains that truly infuriatingfirst-personal经历过拼命尝试，却悲惨地无法入睡吗?

What explains this, I venture, is that falling asleep is not something youdo.

What do I mean by that? I mean that falling asleep is not amental action.

A mental action is something you do in thought. Some examples of mental action are: counting to ten; dividing 36 by three; imagining something to eat; rehearsing your lines before a play. Even though you can do all these things without moving parts of your body—as inbodilyaction—they are still things you do.

There are many different ways to sort mental actions into philosophically interesting categories. What’s relevant here is just one distinction between some mental actions and others. Sometimes when you perform a mental action, you determine exactly what you’re going to be thinking ahead of time. This is the case when you count to ten.

In other cases of mental action, you don’t pickpreciselywhat you’ll think ahead of time. Performing this second kind of mental actions involves letting yourself be guided towards a determinate outcome that meets some target description.

Here’s an example: recalling when you last spoke with your mother. You canchoose要做到这一点。但是，当你开始回忆最后一次和母亲说话的时间时，你还没有确定最后你会怎么想(例如，你会对自己说:“哦，我只是随机选择相信我上周四和她说过话”)。如果你选择了这个，你就不会真的回忆起什么;你只是在胡编乱造。为了算算搞清楚某件事——包括追寻真相——你必须让自己被过去的各种事实所引导。

So in some cases of mental action, you have a complete conception of what you’ll think to yourself ahead of time, because you’ve already chosen it—as in the case of counting to ten. In other cases of mental action, you know whatkindof thing you’re after in thought—e.g. the truth about when you last spoke to your mother—but you don’t pick ahead of time what you will end up thinking.

Which kind of thing isfalling asleep?

I think it is neither. It’s not a mental action at all. It’s not even the kind of mental action where youtryto do somethingbyletting yourself be guided towards some specific type of thought. The outcome needed here is not some specific kind of thought (e.g. a recollection of when you last spoke to your mother last) but a total shutdown of mental action altogether, a complete surrender to a bodily process.

This is just a hypothesis, but I think it’s a promising one which can help us understand why it can feel so difficult to fall asleep. If falling asleep involves doingnothingmentally, then falling asleep is not justdifficultto do; it’s something that you categorically cannot do. It’s not something youdoat all.

Is there any sense at all, then, intryingto fall asleep? If my hypothesis is correct, then trying to fall asleep looks utterly self-defeating. It involves trying to perform no mental actions at all. Buttryingto perform no mental actions at all is itself something you do mentally: a mental action!

However, there is some subtlety here. You cantryto fall asleep in the same sense in which you can try to sneeze on command. This involves putting yourself in a position in which an involuntary process takes over. To help sleep take over, you can take a hot bath; you can put on some white noise; you can (it is said) drink some warm milk.

令人惊讶的是，你甚至可以尝试做一些心理活动来入睡。The catch is that you have to do something so boring and easy that you’ll eventuallystop tryingand let some automatic process take over the task for you.

A canonical example is counting sheep. If what I say about falling asleep is right, then yourcounting sheep on purposeis not what lets you fall asleep; it’s your tendency togiving the task overto a mindless routine that lets you fall asleep. The counting of sheep just crowds out other mental actions that you are less likely to give over to some such automatic process.

Here’s the suggestion, in short: falling asleep isn’t something youdomentally, like solving a math problem or choosing a dish from a menu. On the contrary, what seems central to falling asleep isnot进行任何心理活动。

If my proposal is right, it could help explain the infuriating phenomenology oftryingto fall asleep. Any attempt to fall asleep is necessarily oblique. You can put yourself in a position in which it’s likely that unconscious processes take over your stream of thought. But ultimately what matters to your success is that youstoptrying to do things, and let such processes take over.

This hunch of mine follows in the footsteps of some other philosophical proposals about the relationship between mental action and sleep.Brian O’Shaughnessy, in his 2000 bookConsciousness and the World, argued that dreaming involves a kind of mental paralysis which explains why our dreams make so little rational sense as they evolve.Matthew Soterioupicked up the discussion in his 2013 bookThe Mind’s Construction.

I’m not sure about this point, but Iamsure there is an important (and still under-studied) connection between mental action and sleep. Philosophers must contribute expertise alongside scientific research to understand fully, from a first-personal perspective, why itfeels很难入睡——至少对我们这些失眠症患者来说是这样。