Are There Beings Humans Are Not Equipped to Sense

Imagine you are blind and deaf. You are locked in a hotel room with a fisherman. Can you sense their presence? Perhaps by smelling their fishy odour, or maybe by reaching out and touching them. You will not only know they are there. You may even be able to work out what they do for a living. But what if you had no senses at all that could detect them? They would not cease to be. They would be there, and you would be there too, sharing the same air, the same space, the same moment — and you would have absolutely no way of knowing they existed.

That thought experiment is where this whole thing starts for me. It seems simple enough, even obvious. Of course you cannot detect something you have no mechanism for detecting. Of course the absence of perception does not equal the absence of the thing. And yet, when we apply that logic to the world at large — to the universe humming around us right now — we seem to forget it entirely. We walk around as though our five senses constitute some kind of complete inventory of reality. As though the universe were considerate enough to only put things in it that we can see, hear, smell, taste, and touch.

It did not. It almost certainly did not.

The Poverty of Our Senses

Let us begin with what we do have, because it is easy to take it for granted and mistake familiarity for comprehensiveness.

Sight. Sound. Taste. Touch. Smell. Those are the famous five, the ones schoolchildren learn, the ones that feel as though they constitute a full set. But even that list is incomplete before we get to the interesting part. Humans also have proprioception — the sense that tells you where your body is in space without looking at it. Close your eyes and touch your nose. You can do it because receptors in your joints, muscles, and tendons are continuously feeding your brain a map of your own body. We have a vestibular sense that detects acceleration and gravity, giving us our sense of balance. We have interoception — the ability to sense our own internal states, hunger, thirst, fatigue, the tightening in your chest before a difficult conversation. Some researchers argue this is the most fundamental sense of all, the one that makes us feel like we are alive rather than merely processing.

So we have more than five senses. But even with all of them, we are working with a remarkably narrow window onto reality.

Consider light. The electromagnetic spectrum is vast — it runs from radio waves with wavelengths the size of buildings, down through microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays with wavelengths smaller than an atom. The entire range of light that human eyes can detect sits in a thin sliver roughly between 380 and 700 nanometres in wavelength. That is the visible spectrum. Everything else — the overwhelming majority of the electromagnetic universe — is invisible to us. We live inside a single, thin page of a very long book, and we call it the whole library.

Sound is similarly constrained. Humans generally hear frequencies between about 20 and 20,000 hertz. Dogs can hear up to 65,000 hertz. Bats navigate by echolocating at frequencies up to 100,000 hertz, bouncing ultrasound off insects and reading the returning echoes with a precision that puts any human sense to shame. Elephants communicate across kilometres using infrasound below 20 hertz — rumbles so low we cannot hear them, vibrations we cannot feel, conversations passing through us unnoticed. Whales sing to each other across ocean basins in frequencies that travel for thousands of kilometres through the deep sound channel, a layer of water that acts like an acoustic highway. We swim in a world full of communication we cannot participate in and cannot even perceive.

Smell deserves particular attention because we tend to think of it as something we are reasonably good at. We are not. A dog’s nose contains roughly 300 million olfactory receptors, compared to about six million in a human. Their brain devotes proportionally forty times as much space to analysing scent. Trained dogs can detect certain cancers in a person’s breath. They can follow a trail hours old across kilometres of disturbed ground. Bears have been documented navigating to food sources from distances of over 30 kilometres, guided by scent alone. For these animals, the world is saturated with information that we move through as though it simply is not there.

But it is there.

Senses We Cannot Imagine

Here is where it gets genuinely strange. Because some animals do not merely have sharper or more sensitive versions of our senses. They have senses we do not have at all. Completely different modalities, entire channels of information about the world that we have no native access to whatsoever.

Sharks, rays, and many other fish can detect electric fields. Every living creature generates a weak bioelectric field — the electrical activity of its muscles and nerves leaks into the surrounding environment. Sharks can detect fields as weak as 5 billionths of a volt per centimetre. This is why a shark can locate a flatfish buried under sand, completely invisible to both eye and nose. The fish is electrically broadcasting its presence, and the shark is tuned to that frequency. From the flatfish’s perspective, it has hidden itself perfectly. It has used every available concealment. It has no idea it is screaming.

Turtles and many birds navigate using the Earth’s magnetic field. They carry biological compasses, clusters of magnetite crystals embedded in their tissues, connected to their nervous systems. A loggerhead sea turtle hatches on a beach in Florida, swims across the Atlantic Ocean, circles through the Mediterranean, and returns to within kilometres of the beach where it was born — guided the entire time by a sense we do not have. The Earth’s magnetic field is real, it is structured, it contains information — the intensity varies with latitude, the inclination angle changes systematically — and for these animals it is as readable as a road sign. For us it is nothing. We feel nothing.

Pit vipers — rattlesnakes, copperheads, bushmasters — have pit organs on their faces that function as infrared cameras. They see heat. Not in a vague, general way, but with enough resolution to track a moving warm-blooded animal in complete darkness, strike with precision, and land their bite on a major blood vessel. The mouse runs in what it believes is darkness. The snake is watching it in high definition.

Reindeer can see into the ultraviolet spectrum, which turns out to be genuinely useful in the Arctic, where snow reflects UV light and many lichens and predator urine appear in stark contrast against white snow — information that is simply not there in the visible spectrum. Mantis shrimp have sixteen types of photoreceptor (we have three) and can perceive both ultraviolet and infrared light, as well as polarised light and circular polarised light. Their visual world is so far beyond ours that we genuinely cannot conceive what it looks like. It is not that it looks like our vision but brighter or more colourful. It is structured differently at a fundamental level.

Dolphins and some other marine mammals have something called magnetoreception and also use electroreception in some species. But perhaps more striking is the lateral line system found in fish and aquatic amphibians — a network of pressure-sensitive cells along the body that allows them to detect the movement of water at extraordinary resolution. A school of fish changes direction in milliseconds, each fish responding to the pressure waves generated by its neighbours, a collective awareness moving through the group like a single thought. They are reading a field of information that we cannot sense at all.

Now here is the question I cannot stop sitting with.

If a shark has a sense we do not have, and that sense reveals an entire category of real information about the physical world — information that is objectively there, that has physical reality, that other creatures have evolved entire nervous systems to process — then what else is there? What other channels of information exist that no animal, anywhere, has evolved to detect? What are we, along with every other creature on Earth, floating in complete ignorance of?

The Machines That Extended Us

Humans figured out, eventually, that our senses were incomplete. And we did what humans do. We built tools.

Radio receivers turn electromagnetic waves in the radio frequency range into sound we can hear. Without the receiver, those waves pass through us constantly, carrying voices and music and data, and we feel nothing. X-ray machines allow us to see inside solid objects, revealing structure that is invisible to light. Geiger counters click in the presence of ionising radiation — gamma rays and alpha and beta particles that are entirely undetectable to any human sense but are very much real and, at sufficient intensity, lethal.

We build cameras that see in infrared, revealing heat signatures — the warm outline of a person in a cold room, the heat map of a building losing warmth through poorly insulated walls. We build magnetometers that map variations in the Earth’s magnetic field, used in geology, in archaeology, in submarine detection. We built gravitational wave detectors — extraordinary instruments that can detect ripples in spacetime itself, distortions in the fabric of the universe generated by colliding black holes and neutron stars a billion light years away, distortions so small they are a fraction of the diameter of a proton. Those events happened. They sent energy rippling outward at the speed of light. The waves passed through us, through the Earth, through everything — and we felt nothing. For a hundred years after Einstein predicted them, we had no way to know. Then we built LIGO, and suddenly we could hear the universe speaking in a language we had never heard before.

Every time we build a new detector, we discover the world was always fuller than we thought.

Radio astronomy revealed that the sky, which appears dark and mostly empty to our eyes at night save for stars, is actually blazing with activity — galaxies, quasars, pulsars, the cosmic microwave background radiation left over from the Big Bang, still filling the universe with ancient energy from 380,000 years after its birth. We were walking around under that sky for our entire history, and we had no idea.

The microscope is perhaps the most consequential example of all. For most of human history, disease was attributed to bad air, spiritual punishment, imbalances of humour, curses, poisonous vapours. The notion that invisible living creatures were the cause of illness was not merely unknown — it was, when first proposed, considered absurd. Bacteria are everywhere. They coat every surface. They live in our bodies in numbers exceeding our own cells. They had been causing disease, and death, and the collapse of armies and civilisations, for as long as humans existed. They were real. They had physical substance, metabolised, reproduced, and killed. And for most of human history, they were simply not there, as far as we were concerned. We did not have the instrument to detect them.

Viruses are smaller still, and required the electron microscope — not invented until the 1930s — to visualise. Prions, misfolded proteins responsible for diseases like Creutzfeldt-Jakob and bovine spongiform encephalopathy, are invisible even to most electron microscopes and were not understood as a distinct type of infectious agent until the 1980s, when Stanley Prusiner proposed the idea to widespread ridicule before winning the Nobel Prize in 1997.

Each of these — radio waves, magnetic fields, bacteria, viruses, gravitational waves — was real before we could detect it. Reality did not wait for our permission.

The Hard Problem of Perception

There is a famous philosophical thought experiment proposed by the philosopher Thomas Nagel in 1974, titled “What Is It Like to Be a Bat?” His point was not really about bats specifically. It was about consciousness and the limits of objective, third-person description. A bat navigates the world primarily through echolocation — bouncing high-frequency sound off surfaces and reading the returning echoes with extraordinary precision. We can describe, in complete scientific detail, how echolocation works. We can map the neural pathways, measure the frequencies, describe the processing algorithms. But none of that tells us what it is like to experience the world that way. What does the world feel like when you experience it primarily as returning sound waves? What is the bat’s subjective experience of a moth in flight?

Nagel’s conclusion was that there is something it is like to be a bat — some subjective character to bat experience — that cannot be fully captured by any objective description. The bat’s phenomenal world is genuinely alien to us. We cannot think our way into it.

Now extend that thought. If the bat’s experience is alien to us, what about a shark experiencing the world partly through electroreception? What about a mantis shrimp with its sixteen photoreceptors, perceiving colours in the ultraviolet and infrared that we cannot even name, let alone imagine? What is it like to navigate using the Earth’s magnetic field, to feel your position on the planet as something directly sensed rather than calculated?

We do not know. We cannot know, not really. We can infer. We can build models. But the experience itself is closed to us.

This matters for our question because it suggests that the universe of possible experience — possible modes of perceiving and interacting with physical reality — is vastly larger than the slice any single species occupies. And that in turn raises the question of whether we have adequately considered what it might mean for other kinds of entities to exist in that space.

What Would an Undetectable Entity Look Like

Let me try to think through this carefully, because it is easy to slip into unfounded speculation, and I want to avoid that while still taking the question seriously.

For something to be genuinely undetectable to us, it would need to either (a) interact with forms of energy or matter that our senses and current instruments cannot register, or (b) interact with forms of energy or matter that our instruments can detect, but in patterns too subtle, too distributed, or too unlike what we expect to have been identified as coming from a discrete entity.

Option (a) is the more dramatic possibility. Is there anything in physics that suggests the existence of matter or energy that could interact with the world in some way but be entirely invisible to our current detection methods?

Yes, actually. There is quite a lot.

Dark matter is perhaps the most striking example. Astronomers and cosmologists have accumulated overwhelming evidence that approximately 27% of the mass-energy content of the universe is made of something that does not emit, absorb, or reflect light. We cannot see it. We know it is there because of its gravitational effects — it bends light from distant galaxies, it affects the rotation curves of spiral galaxies, it shaped the large-scale structure of the universe. There is far more of it, by mass, than the ordinary matter that makes up everything we have ever seen, touched, or measured directly. We do not know what it is. The leading candidates are hypothetical particles called WIMPs (Weakly Interacting Massive Particles) or axions or a range of other possibilities, none of which have been directly detected despite decades of searching.

Dark matter does not interact with electromagnetic radiation. It passes through ordinary matter with almost no interaction whatsoever. If dark matter consists of particles, those particles are passing through you right now, constantly, at enormous speeds, and you feel nothing. If dark matter can form complex structures — and there is ongoing theoretical work about whether certain types of dark matter could, under some conditions, clump into stable configurations — then we have no idea what those structures might look like or do. We would have essentially no way to study them with current methods.

This is not science fiction. This is the current state of cosmology.

Dark energy is another unknown. Whatever is causing the expansion of the universe to accelerate, driving galaxies apart at an increasing rate, makes up roughly 68% of the total mass-energy budget of the universe. We call it dark energy because we do not know what it is. It does not interact with matter in any familiar way. It is not detectable by any instrument we have. It is present everywhere, shaping the large-scale fate of everything, and we cannot sense it at all.

Then there is the question of quantum mechanics. The quantum world operates by rules that are genuinely alien to our everyday intuitions. Quantum superposition, entanglement, the collapse of the wave function — these are not metaphors, they are descriptions of how matter actually behaves at small scales. The quantum world is not somewhere else; it underlies everything we interact with. But our senses evolved to navigate the classical, macroscopic world, and they give us no direct window onto quantum reality at all. We have had to build instruments and develop mathematics to even begin to describe it. And physicists are not certain we have the full picture.

Some theoretical frameworks in physics — certain interpretations of quantum mechanics, certain approaches to quantum gravity — suggest that reality has more structure, more layers, more dimensions than we can directly perceive. The mathematics of string theory, for instance, requires ten or eleven spatial dimensions to be internally consistent, with the extra dimensions “compactified” at scales too small to detect with current technology. Whether string theory correctly describes reality is an open question. But the fact that serious physicists take seriously the idea that reality has more structure than we can see is itself significant.

The Consciousness Question

Here is where the essay risks losing the careful reader, so let me be clear about what I am and am not claiming.

I am not claiming that there are ghosts. I am not claiming that angels or demons are real. I am not making any specific claim about the supernatural, because the very word supernatural implies something that operates outside nature, and my argument is actually the opposite — that nature itself is larger and stranger than our current perception of it.

What I am asking is this. Given everything we know about the narrowness of our sensory apparatus, given the history of discoveries that have repeatedly revealed the world to be fuller than we thought, given the existence of real physical phenomena that we cannot directly sense — is it reasonable to assume that we have a complete census of the entities that exist?

The answer, surely, is no.

But I want to push further than just “there might be undiscovered physical phenomena.” I want to ask specifically about consciousness and about entities that might, in some sense, have experience.

Consciousness is the most philosophically troubling thing in the universe. We do not know what it is. We do not know why there is something it is like to be a creature with a certain kind of nervous system. We do not know where, on the spectrum from simple to complex organisms, experience begins and ends. We do not know whether consciousness is produced by biological neural networks specifically, or by any sufficiently complex information-processing system, or whether it is in some sense fundamental to reality itself.

That last possibility — that consciousness might be a fundamental feature of the universe rather than an emergent property of certain biological systems — is taken seriously by some philosophers and physicists under the label of panpsychism. The philosopher David Chalmers has argued extensively that the standard physicalist account of consciousness faces a “hard problem” that has not been solved and may be unsolvable. Why does any physical process give rise to subjective experience at all? Panpsychism, in various forms, proposes that experience is a fundamental feature of reality, present in some basic form throughout the physical world, and that what we call consciousness in humans is a particular, complex form of something more widespread.

I am not advocating for panpsychism here. But I am noting that we do not have a settled, agreed-upon theory of what consciousness is or where it comes from. In that context, strong claims about which entities do and do not have experience seem premature.

What the Psychedelics Might Be Pointing At

And now for the part of this that I find genuinely impossible to dismiss, even though it is the most difficult to talk about without sounding like someone who needs a good sleep.

Psychedelic compounds, and dimethyltryptamine in particular, produce experiences that are unlike anything else in the pharmacopoeia of human consciousness alteration. DMT is endogenous — produced naturally by the human body, though its function is unknown. It occurs throughout the natural world, in hundreds of plant species, in the cerebrospinal fluid of rats, possibly in the pineal gland during certain states. It is, in a sense, part of us.

When administered in sufficient doses, DMT produces what a remarkable number of independent users across different cultures, backgrounds, and contexts describe as contact. Not vivid imagery. Not hallucinations in the sense of seeing things that feel obviously unreal. Contact — with entities, beings, presences that feel more real, not less real, than ordinary waking experience. These entities are frequently described as having their own agendas, their own personalities, their own modes of communication. They are described as knowing things the user does not know. They are described as ancient, or non-human, or existing in a place that feels like another dimension of reality.

The similarity of these reports across different cultures and individuals is striking. Researchers at Johns Hopkins and Imperial College London have conducted survey studies of DMT experiences, and the consistency of the encounter reports — entities perceived as benevolent or at least non-threatening, the sense of entering a different realm, the feeling that the experience is more real than ordinary consciousness — is notable.

Now. What does this mean?

I want to be careful here because there are several possibilities, and the evidence does not clearly distinguish between them.

The first possibility is that DMT produces a specific disruption of the brain’s normal sensory and perceptual processing in a way that generates internally consistent experiences that feel real but are entirely products of the brain itself. On this view, the “entities” are characters generated by the same imaginative apparatus that produces vivid dreams, and their apparent independence is an artefact of the way conscious experience is constructed. This is the orthodox neuroscientific view, and it is perfectly reasonable.

The second possibility is that normal consciousness acts as a kind of filter — that the brain is not a generator of experience so much as a reducing valve, as Aldous Huxley proposed in “The Doors of Perception,” drawing on Henri Bergson’s earlier work. On this view, the brain’s normal function is to limit the range of experience to what is relevant for survival and navigation of ordinary reality, and certain compounds disrupt that filter, allowing a broader range of signals through. The question then becomes. Signals of what?

The third possibility — and this is the one I am not prepared to simply rule out — is that the experiences point toward something real about the structure of reality that we do not understand. That the entities encountered are, in some sense, there. Not physically present in the ordinary sense, perhaps. But real in whatever sense is appropriate to their nature.

I am not saying the third possibility is correct. I am saying that the honest epistemological position — given everything else we have covered in this essay — is that we cannot confidently say it is wrong.

The history of science is, in part, a history of things that seemed obviously impossible turning out to be real. Continental drift seemed absurd for decades. The germ theory of disease was ridiculed. Quantum entanglement, which Einstein called “spooky action at a distance” and considered clearly impossible, turns out to be not just real but potentially foundational to our understanding of quantum mechanics and now quantum computing. The universe does not care about our prior intuitions.

The Asymmetry of Detection

There is something important to notice about the structure of this problem, and it is what I started with. The asymmetry between detecting and being detected.

A blind person cannot see you. But that does not stop you seeing them. A deaf person cannot hear you. But that does not stop you hearing them. Detection is not symmetric. The existence of an entity does not depend on your ability to perceive it. And critically, the question of whether an entity can perceive you is independent of whether you can perceive it.

This means that if there are entities we cannot detect — whether because they interact with forms of energy we have no access to, or because they exist in dimensions we cannot sense, or because the physical correlates of their existence are too subtle for our current instruments — some of those entities might nevertheless be able to perceive us. We might be, from their perspective, perfectly visible. Open books. Screamingly obvious. The flatfish under the sand, broadcasting our presence to the shark.

This is not a comfortable thought. It is not meant to be. But it is worth sitting with.

The Epistemic Humility We Owe the Question

We tend, as a species, to mistake the map for the territory. We build models of reality — sensory, scientific, cultural — and then treat those models as though they are reality itself. It is an understandable mistake. The models work extremely well for navigating everyday life. But they are not complete.

Science is an ongoing project, not a completed one. Every generation has believed, to some extent, that it stood near the end of inquiry, that the major questions were settled or nearly settled. Every generation has been wrong. Lord Kelvin famously suggested, around 1900, that physics was essentially complete — that future work would consist of filling in the sixth decimal place of known constants. Within a few years, relativity and quantum mechanics had overturned the entire edifice.

We are not at the end of inquiry. We are almost certainly not close to it.

What we know. Our senses are narrow, evolved instruments that give us access to a small fraction of the information available in the physical world. Countless real phenomena — entire portions of the electromagnetic spectrum, dark matter, dark energy, the quantum realm — are invisible to unaided human perception. Other animals have sensory modalities we completely lack. Every time we have built a new instrument capable of detecting something we could not previously perceive, we have discovered that the world was already full of it. And we have no complete, satisfactory theory of consciousness — we do not know what gives rise to experience, where it begins and ends, or whether it might be a more fundamental feature of the universe than we currently assume.

What follows from this. The claim that we have a complete inventory of the entities that exist in our universe — or even in our immediate environment — is not supported by the evidence. It is a faith claim dressed as a scientific one.

The more honest position is one of genuine openness. Not credulity — not accepting every claim about spiritual entities or paranormal phenomena at face value. But not dismissal either. The question deserves to be taken seriously, because the thing that would make it absurd — the idea that we can perceive everything there is to perceive — is demonstrably false.

What We Do Not Know

I want to end by sitting with the not-knowing for a moment, because I think that is where this essay actually lives.

We do not know if there are forms of consciousness that do not require biological neurons. We do not know if consciousness can exist in systems that interact with the physical world in ways we currently cannot detect. We do not know what dark matter is made of, whether it can form complex structures, or what properties such structures might have. We do not know whether quantum mechanics, correctly interpreted, implies a reality far richer and stranger than the one we experience. We do not know what the DMT entities are. We do not know whether Nagel was right that certain subjective experiences are genuinely alien and inaccessible to us, or whether we could, in principle, expand our understanding to encompass them.

The universe is large. It is old. It is not built around human convenience or human comprehension. Life on Earth has been discovering new sensory modalities, new ways of being in the world, for hundreds of millions of years. The idea that human consciousness, in its current form, represents the pinnacle or the completion of that process — that we happen to perceive everything worth perceiving — seems unlikely to the point of absurdity.

Something is probably there that we cannot see. Possibly many somethings. The question of whether any of those somethings are in any meaningful sense alive, or conscious, or aware of us — that question deserves to be taken seriously rather than dismissed. It is one of the largest questions we can ask, and our current epistemic position is that we genuinely do not know.

I find that fact simultaneously terrifying and wonderful. It means the universe is stranger than we think. It always has been.

We are the flatfish under the sand, absolutely convinced we are hidden.

What do you think? Are we missing something fundamental about the nature of reality? Let us know in the comments below.