How Do You Know You Are Awake?

Bölüm metni

Right now you are certain you are listening to this. Last night, inside your dream, you were exactly this certain that everything was real. From the inside, how do you tell the two apart — and if you cannot, what are we actually claiming when we say "I know"?

Gecenin bir yerinde uyanıyorsunuz.

Somewhere in the night, you wake up. The room is dark, the blanket heavy, your toes are cold. You roll over and check your phone: it is a little past 3. A moment ago you were somewhere else entirely — walking down the hallway of a house you had never seen, or explaining something to someone you had not laid eyes on in years. Now you are awake, and you know it. You know it without a flicker of hesitation.

But on what grounds? Ask yourself: what exactly did you do to reach that verdict? Did you test the texture of the sheets, probe the reality of the light? No. You did nothing at all. You knew you were awake from the sheer fact of being awake. That is a circular answer, and this is where the discomfort begins — because half an hour earlier, walking down the hallway of that unfamiliar house, you did not doubt for a single instant that you were there.

The strangest thing about a dream is not its content. It is its certainty. In dreams, people fly, dead relatives drink tea in the kitchen, you find your own house in a city you have never visited — and you do not object. The scene you will call absurd in the morning contained nothing absurd at all while it was running. What is more, you can dream that you have woken up. It is called a false awakening: you see yourself getting out of bed, opening the curtains, even writing your dream down in a notebook — and then you wake up for real and find the page blank. Some people go through this several times in a row.

Dream laboratories have gathered one consistent detail over the years: reading is hard in dreams. You look at a sign, a page of a book, a phone screen — the letters will not hold still, the words change on second glance. A digital clock displays something nonsensical. The face in the mirror is not quite your face. All of it is right there, out in the open, and the person in the dream notices none of it. And there is the knot of the problem. A dream does not fool you because it is a good illusion; it fools you despite being a bad one, because there is nobody inside it to raise a doubt.

Brain imaging gives us a solid clue as to why. In REM sleep, where dreams cluster, the visual and emotional regions run almost as hard as they do in waking life — sometimes harder. The frontal regions behind the forehead, meanwhile, the ones that handle comparison, planning and self-monitoring, fall largely silent. So in a dream there is a scene, there is music, there is feeling; what is missing is the editor, the one who says hold on a second. The organ that audits what you see is asleep.

But not always. Some people, right in the middle of a dream, while the dream is still running, realize that it is a dream. It is called lucid dreaming, and we have measurements of how common it is: a review published in 2016, pooling 50 years of research, reports that 55 percent of people have experienced it at least once in their lives, and that the share who experience it weekly or more often sits at around 23 percent. Imaging studies show that at the moment of lucidity, some of those silenced frontal regions come back online. The auditor wakes up; the scene carries on.

For a long time this was a story people told, not something anyone had proved. Because when someone says that in their dream they realized they were dreaming, all you have is their report, delivered in the morning. In 1975, in Britain, a researcher named Keith Hearne tried something simple to get past that. He made an arrangement with his volunteer, Alan Worsley: if you become lucid inside the dream, move your eyes left and right in the pattern we agreed on beforehand. Eye movements still reach the muscles during sleep, because the eyes are one of the few places spared from REM paralysis. That night, in the middle of deep REM sleep, the pen of the recording device traced the agreed-upon signal. A sleeping human being had sent a message to the outside world. Hearne published his finding in an obscure journal and it went largely unheard; the work was taken seriously only when Stephen LaBerge, who developed the same method independently, published his Stanford study in 1981.

What came next is more startling still. In 2021, four separate laboratories in four countries published a joint experiment: with 36 participants, during REM sleep confirmed by sleep recordings, they attempted two-way communication. The sleeping person was asked a question out loud — a simple subtraction, say, 8 minus 6. The answer came back through eye movements or through selected contractions of the facial muscles. From 6 participants, a total of 29 correct answers were recorded. Asking a sleeping human a question and getting the right answer is now something that can actually be done.

So waking and sleeping are not two sealed rooms with no door between them. It is something that can be noticed. And if it can be noticed, it is a skill; and if it is a skill, it can fail. Which leaves exactly one question: by what test? There are two men who pushed that question all the way to the end — one in Baghdad, and one in the Netherlands, sitting beside a stove.

In 1641, Descartes published the Meditations on First Philosophy, and it opens with something almost without precedent in the history of philosophy: the author resolves to bring down everything he knows, not piece by piece, but all at once. Dealing with beliefs one at a time takes too long; the clever move is to demolish the foundation. A stick in water looks bent; a distant tower looks round, and then turns out to be square as you approach. The senses deceive — this much was already known. But in the Meditations he climbs one step higher: right now, sitting by the stove, in my dressing gown, this paper in my hand — how could I doubt that? The answer: I have dreamt exactly this, in exactly this much detail. I can find no certain sign that separates waking from dreaming.

Descartes does not stop there. What about mathematics? In a dream, too, 2 and 3 make 5; in a dream, too, a square has four sides. Shapes, numbers, the simplest chains of reasoning seem immune to illusion. And it is at that point that the coldest idea in the text arrives: suppose there is a being of immense power and immense cunning, who has devoted all of that power to deceiving me. The evil demon. Then it is not only what I see that belongs to him, but that very feeling of certainty I have while counting. It could be a confidence planted in me every time I add 2 and 3. And so the last solid ground beneath my feet gives way as well.

Descartes did not do this in order to destroy knowledge; he was looking for one single point that would not collapse, and he found it. However much I am being deceived, there is someone being deceived. I think, therefore I am. Out of all that demolition, one thing came through alive: the existence of someone in the act of thinking.

Along a path remarkably close to this line of reasoning, 5 and a half centuries before Descartes, someone else had walked — inside an utterly different life. Al-Ghazali was born in 1058 in the city of Tus, in Khorasan, and by his early thirties he was heading the Nizamiyya madrasa in Baghdad, the most prestigious chair in the Islamic world of his day. Hundreds of students, the prestige of the state, an authority beyond dispute. At this point in his life, by his own account, the question of the certainty of knowledge began to break him down from the inside.

In the small autobiography he wrote in his mature years, al-Munqidh min al-dalal, that is, The Deliverance from Error, this is what he describes: he was searching for certain knowledge, knowledge that no doubt could gnaw at. First he saw that he could not trust the senses. Then he turned to reason, but there too a voice rose up. The most unsettling passage in The Deliverance from Error runs like this: while asleep, you believe the things you see are certain; when you wake, you realize none of them corresponded to anything. So who guarantees to you the reliability of what you now receive, awake, from the senses and from reason? Perhaps there is a state beyond waking, and waking stands to it exactly as dreaming stands to waking. Al-Ghazali ties this possibility to the states the Sufis describe and to what comes after death; he recalls a saying attributed to the Prophet: people are asleep, and when they die they wake.

For al-Ghazali, this period did not stay a mere exercise on the page. In his own words, the condition lasted about 2 months, and throughout that time he was, not in word or in claim but in fact, a complete skeptic. And what ended it was not a proof either; by his account, it was a light that fell into his heart. Years later, in the middle of 1095, that same upheaval found an answer in his body this time. For something like 6 months he was torn between two sides: on the one hand the chair, the standing, the salary; on the other, the sense that none of it rested on anything. In the end his tongue froze. He could not speak; he would open his mouth to teach, and no sound would come. Physicians examined him and said the cause was not in the body. After those silent months he left Baghdad, the chair and his fame behind; for roughly 11 years he travelled to Damascus, to Jerusalem, to Mecca, and for a long time he did not return to teaching.

Two men came to the edge of the same abyss and did different things. Descartes tried to build a bridge of proof across it. Al-Ghazali concluded that no such bridge could be built: to his mind, doubt could not be defeated with doubt's own weapon. Neither of them was playing a game. And neither of them was the first to ask the question.

About 2 thousand years before Descartes, in the fourth century before Christ, a thinker in China named Zhuangzi fitted the same question into a few lines. Here is what he tells us: in his dream he had become a butterfly. Wings beating, delighted to be flying, a butterfly through and through. In that moment he had no idea there was a man called Zhuangzi. Then he woke, and he was that man again. But now he did not know: had Zhuangzi dreamt he was a butterfly, or was a butterfly now dreaming it was Zhuangzi?

The real force of this little story lies in its refusal to look for a solution. Descartes was looking for a way out; al-Ghazali was looking for salvation. Zhuangzi leaves the symmetry exactly as it stands. For him, the error is in stamping one of the two states with this is the real me and declaring the other false. Because the fixed I that would do the stamping is itself part of the problem. Elsewhere he speaks of people who weep on waking because they dreamt of a feast, and of people who go out hunting on waking because they wept in their sleep, and he adds this: people imagine they are awake. What Zhuangzi does is not to close the question but to learn to live with it. The answer Eastern thought gives to this matter is usually not a proof, but a stance.

But at another corner of that same part of the world, there was someone who looked at the question as if it were evidence itself. Ibn Sina was born near Bukhara in 980 and died in 1037, and in his monumental work, the Kitab al-Shifa, that is, the Book of Healing, in the section on the soul, he set up one of the cleanest thought experiments in the history of philosophy. He puts it like this: imagine that a human being were created at this very moment, fully grown, in empty space. Suspended in midair. The limbs do not touch one another, there is nothing to see, nothing to hear, nothing to touch, no past, not a single memory. Such a being could know nothing. Nothing at all? Ibn Sina's answer: it would know its own existence. It would not know its hand, it would not know its body, it would not know the world — but it would know the I.

The purpose of this experiment in the Book of Healing was not to answer the doubt raised by dreaming; Ibn Sina was trying to show that the soul is not the same thing as the body. The method, even so, is strikingly the same: strip everything away, and look at what cannot be stripped. And the thing that cannot be stripped away lands, startlingly, in the same place as what would be discovered in Europe 6 centuries later: the existence of the subject itself. This is not identical to Descartes's sentence, and it would be unfair to claim the two are saying exactly the same thing — but on the question of what could possibly survive the scythe of doubt, two traditions arrived at a similar place.

It is worth saying, too, how thin that foothold is. The man suspended in the air is certain of his own existence, and that is all. He does not know that the room is real. He does not know that the person sitting at the table across from him, whose voice he recognizes, with whom he has lived for years, is real. So this solid point is not a foundation on which a life can be built; it is a ledge grabbed by someone going under. Descartes filled the gap between them with the idea of a God who would not deceive him. Al-Ghazali filled it with a light descending into the heart. Zhuangzi refused to fill it at all.

And for centuries this entire argument remained a cool-headed thought experiment. Because to have someone command all of your senses at once, you really did need a demon. Now a laptop will do.

The sentence I saw it with my own eyes ends the argument in almost every language. Not hearsay, not secondhand, not interpretation; I saw it. The whole architecture of human certainty rests on that sentence. The witness in court, the journalist's recording, the family's oldest photograph, all of it.

In January 2024, in Hong Kong, a finance officer working in the local office of the British engineering firm Arup received a message from the chief financial officer in London about a confidential transaction. The man's first reaction was the right one: this could be a scam. Then he joined a video call. Across from him was the chief financial officer, along with several other familiar colleagues; their faces were their own faces, their voices their own voices, their manners of speaking their own. After the meeting, he had no hesitation left. He sent a total of 200 million Hong Kong dollars, roughly 25 million US dollars, to 5 separate accounts across 15 transactions. When Hong Kong police announced the case in February 2024, they said this: the only real person in that meeting was the person being defrauded. Everyone else was a synthetic image generated from publicly available video and audio recordings. Arup confirmed in May 2024 that it was the victim.

The real lesson of this story is not carelessness. That officer applied the test. He looked at the faces, he listened to the voices, he recognized them. The test simply no longer worked.

The second and more insidious effect was given a name in a paper written in 2019 by the law professors Robert Chesney and Danielle Citron: the liar's dividend. As the fake becomes convincing, the genuine recording loses its force too. Anyone caught on camera now has a ready answer: that was generated. So the aim of the new deception is not to make you believe a lie; it is to leave you unable to believe anything. This is the cheap, realistic version of Descartes's demon. It does not need to command all of your senses; it is enough to command the channel through which you learn about the world.

So what is any of this good for? Here is where the real residue of a 400-year-old argument, the part that is useful today, comes into view, and it is not individual certainty. Remember where the dream was weak: it was not in vividness. A dream is vivid, it is persuasive, it is emotionally stronger than waking life. Where the dream fails is consistency. The writing changes on second glance, clocks talk nonsense, the staircase you climbed does not bring you back to where you climbed from. And this is exactly the method lucid dreamers use: they do not look at a beautiful landscape and say that it looks so real; they look at a piece of writing twice. Because an illusion holds up to a single glance; it does not hold up to being tugged at from several directions.

So the right question was never whether something looks real; it was whether it holds together when you pull at it from several directions at once. What a newsroom calls confirmation, what a court calls mutually corroborating evidence, what science calls independent replication, all of it is the same move: for a lie to stay standing, many unconnected threads have to have been woven at the same time, and woven so that they agree with one another. That is also the logic behind the work being done today on standards that would have cameras embed provenance information into an image at the very moment of capture: the file carrying the record of where it came from on its own back. None of this delivers certainty. All of it does the same thing: it raises the cost of forgery.

And in the end, this is what remains: wakefulness is not a condition you test once and then pocket, but a labour you keep up. The man who gave this answer most plainly was the one who paid the steepest price for the question. Years later, in 1106, al-Ghazali began teaching again in Nishapur, and he did not do it because he was holding some proof that refuted doubt. He had written that no such proof could ever be found. Even so, he returned to living, to teaching, to passing judgment; because the answer to doubt was not to be found in doubt's own language, but inside a life. Descartes left his demon behind in the first meditation and spent the rest of his life building. Zhuangzi kept the question open and did not chase the butterfly. And Ibn Sina's man suspended in the air is still there: not touching, not seeing, not remembering, yet existing.

The person inside the dream never asks whether they are awake. Asking that question is not proof of wakefulness — but it is wakefulness's only habit.

Nöron Philosophy'de bugünkü bölümün sonuna geldik. Yeni bir hikâyede yeniden buluşmak üzere.