I'm not asking what happens in the body while we sleep. Nor do I simply want to know what substances the brain produces, how memories are consolidated, or what the consequences of insomnia are. Science has provided valuable explanations for those functions. My question lies a little further back, in a much more uncomfortable place: why was life structured in such a way that it needs sleep?
Why must almost all known animals periodically relinquish vigilance, will, and conscious engagement with the world? Why did evolution preserve a condition that leaves the individual immobile, defenseless, and exposed to any danger? Why weren't we designed to repair ourselves while awake?
We can eat while we walk. We can breathe while we think. Our heart continues to work without requiring us to disconnect. Our tissues regenerate, our blood circulates, and our cells exchange energy while we go about our activities. However, there is a set of fundamental processes that seemingly require us to be absent.
For several hours each day we have to disappear.
A flaw that is too dangerous
From the basic logic of survival, sleeping seems like a mistake.
A sleeping animal doesn't hunt for food, reproduce, protect its young, or react quickly to predators. For a considerable part of its life, it remains partially or completely disconnected from its environment. If natural selection eliminates harmful traits, how did sleep manage to survive for millions of years?
The immediate answer would be that its benefits outweigh its dangers. That's probably true. But that still doesn't solve the mystery. It only confirms that sleep is so essential that life is willing to pay a huge price for it.
Sleep appears, with enormous variations, in mammals, birds, fish, reptiles, insects, and even in organisms with extremely simple nervous systems. Some species have developed extraordinary solutions: they sleep for minimal periods, rest while flying, or allow one part of the brain to sleep while the other remains alert. But even these adaptations seem unable to completely eliminate the need for sleep.
Life bargains with dreams, reduces them, divides them, and disguises them. What it apparently cannot do is get rid of them.
That's what arouses my suspicion.
Science describes the mechanism, but it does not exhaust the question
We know that memories are consolidated, emotions are regulated, and information is reorganized during sleep. There is also evidence that certain brain cleaning processes function particularly efficiently during deep sleep. None of this is small or irrelevant.
But explaining what happens during sleep does not necessarily equate to explaining why existence was organized in that way.
Saying we sleep to consolidate memories is similar to saying we go to a garage because our car is repaired there. The explanation describes the garage's usefulness, but it still raises another question: why was the vehicle built in such a way that it had to stop completely for that maintenance?
The brain doesn't shut down when we sleep. Its activity changes. During REM sleep, associated with our most intense dreams, some brain regions show activity comparable to wakefulness. The thalamus can send images, sounds, and sensations to the cortex while the body remains virtually immobile.
From the outside we seem absent. Inside us, a whole experience may be unfolding.
We build places, hear voices, experience fear, pleasure, pain, and desire. We encounter dead people. We visit nonexistent spaces and accept absurd situations as normal. We can live a story that seems to last for hours and wake up when only a few minutes have passed.
Why does the brain need to produce all that while it's supposedly resting?
The usual explanation holds that dreams are a consequence of nighttime brain activity: a mixture of memory, emotion, and neuronal reorganization. That's possible. But such a constant, complex, and compelling consequence deserves at least some skepticism.
What if sleeping wasn't resting?
My theory is not scientific. I don't intend to present it as a proven truth. It's a suspicion, a possibility born from a question that science hasn't yet fully answered.
What if sleep were not only a need of our body, but an obligation related to something outside of it?
The idea may seem outlandish, but sleep itself is already so. Every night we voluntarily relinquish control of our bodies, diminish our capacity to react, and allow another form of consciousness to take our place. We don't choose the images we will see. We don't decide who will appear. We don't control how much we will remember upon waking.
We surrendered.
Perhaps during sleep our consciousness shifts to a level of reality that we cannot perceive while awake. It could be another dimension, a shared mental space, or a condition of existence for which we do not yet possess the means to observe.
I'm not claiming that so-called astral travel exists as it's usually described. I wonder if that ancient belief could be a primitive interpretation of a real experience whose mechanism we don't understand. Cultures that never had contact imagined that during sleep some part of the self left the body. Perhaps it was superstition. Perhaps it was the available way to name a universal sensation.
When we dream, we don't feel like we're watching a screen inside our head. We feel like we're there.
Who needs our dreams?
There is an even more unsettling possibility: what if something needed that activity?
Humans have discovered organisms that live inside others, species that feed on substances produced by their hosts, and natural systems based entirely on energy exchange. Life is full of invisible relationships until a tool capable of detecting them appears.
For centuries we were unaware of the existence of bacteria, electromagnetic waves, radiation, and subatomic particles. Not because they didn't exist, but because our senses couldn't perceive them.
That's why I wonder if there could be a form of life, intelligence, or structure that doesn't feed on matter like we do, but on mental activity, emotions, or experiences produced during sleep.
I don't necessarily imagine a creature hiding by the bed absorbing our thoughts. That image would be too human. It could be a much larger, more impersonal system, in the same way that we use solar energy without the Sun even knowing we exist.
Perhaps dreams produce something.
Perhaps fear, desire, memory, and imagination generate a kind of energy we don't yet know how to measure. Perhaps we need it to maintain our identity. Perhaps it's used by another reality. Or perhaps there's an exchange: we give something during sleep and receive that which allows us to wake up restored.
The word “contract” frequently pops into my head. I’m not talking about a document or a religious pact, but a condition inherent in existence. To stay alive, we must eat, breathe, and sleep. No one consulted us about these clauses. We were born into them.
Sleeping could be one of the conditions of the contract for being here.
Obligatory amnesia
Another strange element is that we almost always forget.
We can experience extraordinarily intense dreams and lose them seconds after opening our eyes. We remember an image, a phrase, or a presence, but the rest vanishes as we try to retrieve it.
Because?
Science studies the mechanisms that make it difficult to store dreams as lasting memories. There is even research suggesting that certain neurons may actively participate in forgetting during REM sleep. But the physiological explanation leaves me with the same question: why does the system work this way?
Why can we access an experience and, upon returning, not fully retain it?
The structure feels too much like a border. We enter, participate, and return with fragmented memories. As if we weren't allowed to bring all the information back. As if waking consciousness and sleeping consciousness were two individuals using the same brain, but not sharing all their files.
Sometimes we wake up with an emotion whose origin we can't identify. We feel sadness, relief, fear, or nostalgia for something we no longer remember. The story is gone, but its effect remains.
Perhaps the dream isn't completely lost. Maybe it alters something within us and then erases the process.
The argument from evolution
Someone might answer that there is no mystery: we sleep because evolution found in sleep the most efficient way to conserve energy, repair the body and organize the brain.
I accept that explanation as a reasonable possibility. But even within it, there is something extraordinary.
Evolution isn't an engineer who plans. It works with modifications, advantages, and survival. If sleep has been preserved despite making us vulnerable organisms on a daily basis, its function must lie in a fundamental area of life.
That doesn't prove hidden dimensions, astral travel, or entities that feed on dreams. I don't want to fall into that trap. Just because something is mysterious doesn't automatically make any hypothesis true.
But we must not confuse a partial explanation with a definitive answer.
Science recognizes several functions of sleep, but no single theory can satisfactorily explain all its aspects, all its stages, and all its manifestations in such different species. We continue to study it because the case is not yet closed.
A reality we all experience.
The most surprising thing about dreams is that they are not an exceptional experience. They don't belong only to mystics, the sick, or people under the influence of hallucinogenic substances. Millions of human beings enter a reality fabricated—or visited—by consciousness every night.
We do it even before we understand language.
A child dreams. An old person dreams. A person who denies any possibility of the paranormal also dreams. The skeptic and the believer pass through the same door, although upon waking they interpret it in different ways.
We spend roughly a third of our lives sleeping. If someone lives to be ninety, they may have spent nearly thirty years in that state of absence. Thirty years in which their body was present, but their consciousness did not normally participate in the world.
To call it rest is an understatement. It is another form of existence.
I don't have an answer.
I don't know if we travel to another dimension. I don't know if an unknown intelligence needs our energy. I don't know if dreams are messages, residue, simulations, or scenarios where consciousness processes what it cannot resolve while awake.
Perhaps there is nothing paranormal behind the dream.
It's possible that everything happens inside the brain and that our inability to understand it is simply due to how little we still know about consciousness. But even that answer would be astonishing: it would mean that within every human being there exists a machine capable of producing entire worlds, autonomous characters, landscapes, and emotions without receiving direct information from the senses.
My purpose is not to convince anyone of a theory. It is to defend the right to ask the question without immediately reducing it to a reassuring explanation.
Why do we need to sleep?
Why does life require us to lose consciousness in order to continue?
Why does the brain create another reality precisely when the body stops relating to this one?
Where do we go during those hours?
Did we come back exactly the same?
Perhaps sleep is maintenance. Perhaps it's learning. Perhaps it's a way to protect the brain from itself. Or perhaps every night we perform a function we're still unaware of.
We close our eyes believing that we cease to participate in the universe.
Perhaps that's when we start to get involved elsewhere.
