What Is It Like to Be a Bat?
Based on Wikipedia: What Is It Like to Be a Bat?
You will never know what it feels like to navigate the world through sound. Not really. You might close your eyes and click your tongue against the roof of your mouth, listening for echoes bouncing off furniture. But that parlor trick doesn't even scratch the surface of what a bat experiences when it sends out high-pitched calls and builds a three-dimensional map of the world from the returning sounds.
This impossibility—the unbridgeable gap between your consciousness and a bat's—became one of the most influential ideas in modern philosophy of mind, thanks to a paper published in 1974.
The Paper That Changed How We Think About Consciousness
Thomas Nagel, an American philosopher, published "What Is It Like to Be a Bat?" in The Philosophical Review. It became what philosopher Daniel Dennett—who disagrees with much of it—called "the most widely cited and influential thought experiment about consciousness."
The paper's central claim seems almost obvious once you hear it. Nagel argued that an organism has conscious mental states if and only if there is something that it is like to be that organism. Not something it is like for you to imagine being that organism. Something it is like for the organism itself.
Read that again. It's a subtle but crucial distinction.
When you imagine being a bat, you're imagining what it would be like for you—a human consciousness—to have wings, to hang upside down, to eat insects. But that's not what Nagel is asking about. He's asking what the bat's own experience feels like, from the bat's own perspective. And that, he argues, is something you fundamentally cannot access.
Why Bats?
Nagel didn't choose bats randomly. He was living in a home where bats were frequent visitors, which is a charmingly mundane origin for such an influential philosophical argument. But there's a deeper reason bats work so well for this thought experiment.
Bats are mammals, like us. They have brains, nervous systems, and behavioral patterns that strongly suggest they have conscious experiences. If anything does, bats do.
But bats perceive the world in a fundamentally different way than humans. They use echolocation—emitting high-frequency sounds and listening to the echoes that bounce back from objects. This biological sonar allows them to navigate in complete darkness, catch insects on the wing, and build a detailed picture of their environment.
In some ways, echolocation is analogous to vision. Both are perceptual systems that create a representation of the surrounding world. Both involve detecting something bouncing off objects—light in our case, sound in theirs. But the similarity ends there.
What is it like to perceive the texture of a tree trunk through returning sound waves? What is it like to sense the flutter of a moth's wings as acoustic ripples in the air? What is it like to experience distance not as something you see but as something you hear, encoded in the timing of echoes?
Nagel's answer: we have no idea, and we never will.
The Problem with Imagination
You might object. Surely we can imagine what it's like to be a bat? We can imagine flying through the night sky. We can imagine hanging upside down from a cave ceiling. We can imagine the sensation of echolocation as a kind of sonic vision.
But Nagel points out that this objection misses the point entirely.
When you imagine these things, you're imagining what it would be like for you to have bat-like experiences. You're taking your human consciousness—with its particular ways of organizing sensory information, its particular emotional responses, its particular sense of what feels good or bad—and dressing it up in bat costume.
That's not what it's like to be a bat. That's what it's like for a human to role-play as a bat.
Nagel goes further. Even if you could somehow gradually transform into a bat—growing wings, developing echolocation, shrinking down to bat size—you still wouldn't know what it's like to be a bat. Your brain wouldn't have been wired as a bat's brain from birth. You would experience bat-like behaviors through a brain that developed as a human brain. The inside view would still be fundamentally different.
The Deeper Point: Subjectivity Cannot Be Reduced
The bat example is memorable, but it's really in service of a bigger argument. Nagel is attacking something called reductive materialism, which is the philosophical position that everything about minds and mental states can be fully explained in terms of physical processes.
A reductive materialist might say: consciousness is just neurons firing in certain patterns. If we could map every neuron in a bat's brain and trace every electrical signal, we would have a complete explanation of bat consciousness.
Nagel says: no, you wouldn't.
You would have a complete explanation of the physical processes that correlate with bat consciousness. But you would not have captured what it is like to be a bat. That subjective experience—that first-person perspective—is something that cannot be captured in third-person, objective terms.
Think of it this way. Imagine neuroscientists of the future have perfectly mapped every neural correlate of the color red in your brain. They can predict with perfect accuracy when you will see red, how intense the experience will be, and how long it will last. Have they explained what red looks like to you?
No. They've explained everything about the red experience except the experience itself.
The Single Point of View
Nagel's key insight is that every conscious experience is connected to what he calls a "single point of view." Your experience of reading these words right now is happening from your perspective, from inside your consciousness. That's not a removable feature of the experience. It's constitutive of it.
Scientific explanation aims for objectivity—a view from nowhere, accessible to anyone regardless of their particular perspective. But conscious experience is inherently perspectival. It's always a view from somewhere specific.
This creates a fundamental tension. To explain consciousness scientifically, we would need to somehow translate subjective, first-person facts into objective, third-person terms. But the subjective character is precisely what makes conscious experience what it is. Strip that away, and you've changed the subject entirely.
It's like trying to explain a joke without any reference to what makes it funny. You could describe the setup, the timing, the punchline structure. But if your explanation doesn't capture why people laugh—if it doesn't connect to the actual experience of finding something humorous—then you haven't really explained the joke at all.
The Critics Strike Back
Not everyone found Nagel's argument convincing. Daniel Dennett, one of the most prominent philosophers of mind, offered a pointed response. He argued that any "interesting or theoretically important" features of a bat's consciousness would actually be accessible to third-person scientific investigation.
For example, we know from studying echolocation that bats cannot detect objects more than a few meters away—the sound dissipates too quickly. This tells us something meaningful about the bat's conscious experience: there's a perceptual horizon, a limit to what the bat can sense. Dennett argues that further scientific study could reveal more and more about what bat experience is like.
The philosopher Kathleen Akins took a similar approach. She argued that many questions about bat consciousness actually hinge on detailed neuroscientific facts—questions like what function certain patterns of brain activity serve. Nagel, she suggested, was too quick to rule out scientific answers to his own questions.
Then there's a fascinating counterargument from researchers Eric Schwitzgebel and Michael Gordon. They pointed out that humans actually do use echolocation—we just don't realize it. When you walk through a room with your eyes closed, you're using subtle sound cues to avoid bumping into things. Blind individuals often develop this ability to a remarkable degree, clicking their tongues and listening for echoes much like bats do.
This suggests that the gap between human and bat experience might not be as vast as Nagel supposed. Maybe we have more access to echolocation-like experiences than we think—we're just not consciously aware of it.
The Forty Years of Fresh Confusion
Not all critics were so gentle. The philosopher Peter Hacker called Nagel's paper "malconstructed" and "misconceived," arguing that it "laid the groundwork for forty years of fresh confusion about consciousness."
That's a harsh assessment, but it points to a real concern. Has "what it's like" language actually helped us understand consciousness, or has it just given us a new way to talk about our confusion?
There's something seductive about Nagel's formulation. It feels like it captures something real and important about conscious experience. But critics like Hacker worry that it's a philosophical dead end—a way of gesturing at mystery rather than dissolving it.
Where This Leaves Us
Fifty years after its publication, "What Is It Like to Be a Bat?" remains philosophically influential and unresolved. The paper didn't solve the mind-body problem. If anything, it made the problem seem harder.
Nagel himself ended his paper with a curious note of humility. He argued that we shouldn't conclude physicalism is false—the view that everything is ultimately physical. After all, we don't fully understand what "physical" means. Physics itself keeps revealing that the physical world is stranger than we imagined. Maybe future physics will find a way to incorporate subjective experience.
But Nagel also insisted that we can't really understand physicalism until we have a better handle on the relationship between objective and subjective perspectives. That's the hard work that still needs to be done.
In the meantime, somewhere in the night sky, bats are experiencing something. Their echolocation creates a sonic world we cannot enter. Their consciousness has a texture we cannot feel. And that gap—between their experience and our understanding—remains as mysterious as it was when Nagel first pointed to it.
The Broader Implications
Nagel's paper has implications far beyond philosophy seminars. If he's right that subjective experience cannot be captured in objective terms, this matters for artificial intelligence, for animal ethics, for neuroscience, and for our understanding of ourselves.
Consider artificial intelligence. Could a sufficiently advanced computer be conscious? If Nagel is right, we might never know from the outside. A machine could behave exactly like a conscious being while having no inner experience at all—or it could have rich inner experiences we have no way of detecting. The "what it's like" question applies to AI just as much as it applies to bats.
Or consider animal ethics. We make moral decisions based partly on whether we think animals can suffer—whether there's something it's like for them to feel pain. But Nagel's argument suggests we may be fundamentally limited in our ability to know this. We infer consciousness in other creatures based on behavior and brain similarity, but we can never directly access their experience.
This uncertainty cuts both ways. It might mean we underestimate the consciousness of creatures very different from us—insects, perhaps, or octopuses with their distributed nervous systems. Or it might mean we overestimate the consciousness of creatures that merely behave as if they have experiences.
Even human-to-human understanding takes on a different character in light of Nagel's argument. You will never know exactly what it's like to be another person. You can imagine their situation, you can empathize with their feelings, but their actual inner experience remains fundamentally private. Each consciousness is an island.
The Beauty of the Question
Perhaps the lasting value of Nagel's paper isn't any particular answer but the question itself. "What is it like to be a bat?" is one of those rare philosophical questions that anyone can understand immediately. It doesn't require technical vocabulary or years of study. A child can grasp it.
And yet this simple question opens up profound mysteries. It forces us to confront the strange fact that there is something it is like to be anything at all. Why isn't the universe just physical processes happening in the dark? Why is there an inside to experience?
The bat, hanging in a cave somewhere, doesn't wonder about these things. It just is what it's like to be a bat. But we humans—we get to be puzzled. We get to notice that consciousness is strange, that our inner lives are mysterious even to ourselves.
Maybe that's the most valuable thing Nagel gave us: not an answer, but a sense of wonder at the right question.