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Somebody used this paper to make the term batfished, which they defined as being fooled into ascribing subjectivity to a non-sentient actor (i.e. an AI).

https://partiallyexaminedlife.com/2025/06/30/what-is-it-like...

The problem itself is at least centuries old, if not millennia. In his "Essay Concerning Human Understanding" (1689), John Locke phrased the same problem clearly, using different words:

"How any thought should produce a motion in Body is as remote from the nature of our Ideas, as how any Body should produce any Thought in the Mind. That it is so, if Experience did not convince us, the Consideration of the Things themselves would never be able, in the least, to discover to us." (IV iii 28, 559)

Human beings can, in fact, learn to echolocate, and they seem to experience it as vision, supported by their own descriptions and by fMRIs showing the visual cortex lighting up.

I'm not going to try to draw any inferences about consciousness from these facts. I'll leave that to others.

https://www.npr.org/programs/invisibilia/378577902/how-to-be...

>"An organism has conscious mental states if and only if there is something that it is like to be that organism – something that it is like for the organism."

IMHO the phrasing here is essential to the argument and this phrasing contains a fundamental error. In valid usage we only say that two things are like one another when they are also separate things. The usage here (which is cleverly hidden in some tortured language) implies that there is a "thing" that is "like" "being the organism", yet is distinct from "being the organism". This is false - there is only "being the organism", there is no second "thing that is like being the organism" not even for the organism itself.

“I want to stay as close to the edge as I can without going over. Out on the edge you see all kinds of things you can't see from the center.”

— Kurt Vonnegut

In this sense, I think one has to aaaaaalmost be a bat in order to know what it is to be it. A fine thread trailing back to the human.

The imago-machines of Arkady Martine's "A Memory Called Empire" come to mind. Once integrated with another's imago, one is not quite the same self, not even the sum of two, but a new person entirely containing a whole line of selves selves melded into that which was one. Now one truly contains multitudes.

My favorite (and admittedly unorthodox) companion piece to Nagel's Bat, and one of my favorite literary recommendations, is Vernor Vinge's Hugo-winning 2000 novel, A Deepness in the Sky [0].

It's a hard-sci-fi story about how various societies, human and alien, attempt to assert control & hegemony across centuries of time (at times thinking of this as a distributed systems and code documentation problem!), and how critical and impactful the role of language translation can be in helping people to understand unfamiliar ways of thinking.

At the novel's core is a question very akin to that of Nagel's positivism-antipositivism debate [1]: is it possible (or optimal for your society's stability) to appreciate and emphasize with people wholly different from yourselves, without interpreting their thoughts and cultures in language and representations that are colored by your own culture?

What if, in attempting to do so, this becomes more art and politics than provable science? Is "creative" translation ethical if it establishes power relationships that would not be there otherwise? Is there any other kind?

Deepness is not just a treatise on this; it places the reader into an exercise of this. To say anything more would delve into spoilers. But lest you think it's just philosophical deepness, it's also an action-packed page-turner with memorable characters despite its huge temporal scope.

While technically it's a prequel to Vinge's A Fire Upon The Deep, it works entirely standalone, and I would argue that Deepness is best read first without knowing character details from its publication-time predecessor Fire. Note that content warnings for assault do apply.

[0] https://www.amazon.com/Deepness-Sky-Zones-Thought/dp/0812536...

[1] https://en.wikipedia.org/wiki/Logical_positivism / https://en.wikipedia.org/wiki/Antipositivism

Echolocation for humans 101:

Close eyes, make short impulse-like noise (tapping of feet can be sufficient, or snip fingers), and move slowly.

You will find that not running into walls is pretty easy.

Feedback, to me, feels like light pressure on my face. But this sense can be trained a lot; object detection and mapping your proximity is feasible for trained humans, and presumably changes the perception.

Related - Charles Foster has put perhaps the most effort of any individual to try to really understand what it's like to live as an animal. From the blurb or 'Being a Beast':

> He lived alongside badgers for weeks, sleeping in a sett in a Welsh hillside and eating earthworms, learning to sense the landscape through his nose rather than his eyes. He caught fish in his teeth while swimming like an otter; rooted through London garbage cans as an urban fox; was hunted by bloodhounds as a red deer, nearly dying in the snow.

https://en.wikipedia.org/wiki/Charles_A._Foster

Bandit: "Hey, Bluey! You're a fruit bat!"

Bluey: "Yeah!"

Bandit: "How is it?"

Bluey: "It's great! You get to eat a lot of fruit!"

Both consciousness and experience arise from physical means. However, they are very distinct concepts and not mutually exclusive, which can lead to confusion when they are conflated.

Sensory deprived, paralyzed, or comatose individuals can be conscious but have no means to experience the outside world, and depending on their level of brain activity, they might not even have an "inner world" or mind's eye experience.

Anything that is able to be measured is able to experience. A subject like an apple "experiences" gravity when it falls from a tree. Things that do not interact with the physical world lack experience, and the closest things to those are WIMPs (weakly interacting massive particles). Truly non-interacting particles (NIP) are presumed to be immeasurable.

So there you have it. The conundrum that consciousness can lack experience and unconsciousness can have experience. A more interesting question in my opinion: what is a soul?

I'm less convinced with consciousness as some sort of exceptional phenomenon—and how it's been used to define the "hard problem"—but the paper is still valuable as it provides an accessible entry point into the many problems of reductionism.

Ive wondered if to a bat a bat is more like a whale, swimming through the air, calling out at a rate and pitch sort of matching the distance its electrical signals travel. To them they aren’t moving fast at all, or maybe to them maybe humans are like ents, plodding along so slow talking like ents.

Related. Others?

What is it like to be a bat? (1974) [pdf] - https://news.ycombinator.com/item?id=35771587 - May 2023 (117 comments)

What Is It Like to Be a Bat? (1974) [pdf] - https://news.ycombinator.com/item?id=13998867 - March 2017 (95 comments)

A browser game inspired by Thomas Nagle's Essay “What is it like to be a bat?” - https://news.ycombinator.com/item?id=8622829 - Nov 2014 (3 comments)

Materialism (perhaps physicalism as well) appears to be on shaky ground to me - it does not tell me 'why' I have the first person experience that I have, why I experience and embody the matter that is my person or being, a specific entity. Another way to look at it is to say there doesn't appear to be a region in the brain that defines why I experience the brain, that or this specific brain. From this perspective, I find it self-refuting. They appear only to locate or correlate matter and experience - to help explain 'how'. If I could experience other persons or beings in the first person, and the matter in each person explained why it is that I experience that specific person or entity, I might believe otherwise. To me, this simple fact makes it obvious there is something 'more' that must explain how 'being' relates to consciousness, otherwise, we are simply explaining how the brain modulates experience - very valuable, but less interesting and within reach and validated in everyday life (biochemically and physically, degeneration, damage, etc.). So I would say the brain appears to modulate what is responsible for first person experience. This may not be the correct way to look at consciousness, but it's the most intuitively appealing to me. Because we can't separate being from consciousness, I find the idea that we might create it in the near-term unbelievable. We might certainly create something that can operate with the same or similar results, but I'm not currently convinced it would actually have a subjective first person experience equivalent to the reason we experience the matter we experience. There may be a logical or philosophical way around this view, but as I'm not trained, it's not immediately obvious.

If you are a secular person, it should follow that you are a non-dualist. Yet that is not so common. There's no "whats its like to be a bat". Because that invokes a sense of a "soul" or "spirit" or "self" being transferred from one being to another.

There is only is and its content. That's it. The easiest way to see or get a sense of this is to replace any "I am ..." with "There is a ....". For example, instead of "I am thinking of writing of using stable sort", replace it with "This person have a thought of using stable sort".

This is much closer to the actual reality underneath. Even attachment itself can be put in this term. "There's a feeling that this person own this" or "There's a sense of I".

After doing, perhaps this is mental illness, I already see glimpse of the sense that everything is everything at the same time. As there are no real difference between this rock and the other rock behind the mountain that I can't see. There should be no difference between my thoughts, senses, feelings, emotions etc and that of other people. Now your sense of self captures the entirety of the universe. If you die, the universe dies for all you know. I think this is what the ancient books have been talking about by rising and being a God.

Can a bat answer the question of “what is it like to be a bat?” I mean, I guess they would have to be able to comprehend the idea of being, and then the idea that things might experience things in ways other than how they do. Bats don’t seem like very abstract thinkers.

I bet if we could communicate with crows, we might be able to make some progress. They seem cleverer.

Although, I’m not sure I could answer the question for “a human.”

Dennett has a character telling a story about a bat:

Here's Billy the bat perceiving, in his special sonar sort of way, that the flying thing swooping down toward him was not his cousin Bob, but a eagle, with pinfeathers spread and talons poised for the kill!

He then points out that this story is amenable to criticism. We know that the sonar has limited range, so Billy is not at least perceiving this eagle until the last minute; we could set up experiments to find out whether bats track their kin or not; the sonar has a resolution and if we find out the resolution we know whether Billy might be perceiving the pinfeathers. He also mentions that bats have a filter, a muscle, that excludes their own squeaks when they pick up sonar echoes, so we know they aren't hearing their own squeaks directly. So, we can establish lots about what it could be like to be a bat, if it's like anything. Or at least what is isn't like.

To me, "what is it like to be a" is more or less the intersection of sensory modalities between two systems... but I'm not sure the extent of the overlap tells you much about whether a given system is "conscious" or not.

Maybe in the future we'll be able to run computer simulations of people and bats that think they are conscious and you'll be able to merge them a bit to get some bat experience?

Anil Seth recently wrote a book "Being You", which very much states that we can only know what it is like to be ourselves.

Basically, to know what it is like to be a bat, you need to have evolved as a bat.

His theory that our perception is a hallucination generated by a prediction algorithm that uses sensory input to update and correct the hallucination is very interesting.

Ed Yong wrote an excellent book closely related to this topic titled An Immense World on the sensory lives of animals that we are still only beginning to understand.

"It is all that we know, and so we easily mistake it for all there is to know. As a result, we tend "to frame animals' lives in terms of our senses rather than theirs."

The bat article might be a more philosophical treatise...

But it makes me think of this article:

https://www.grandin.com/references/thinking.animals.html

which is a more concrete(?) dive into being an animal?

>An organism has conscious mental states if and only if there is something that it is like to be that organism—something it is like for the organism.

Isn’t this just the same as saying an organism is conscious if it perceives? If it is aware of input from one or more senses (and I’m not limiting that to the five human senses)?

The article basically talkes about "umwelt" (there is a link at the bottom) - "is the specific way in which organisms of a particular species perceive and experience the world, shaped by the capabilities of their sensory organs and perceptual systems"

How it at all related to let's say programming?

Well, for example learning vim-navigation or Lisp or a language with an advanced type system (e.g. Haskell) can be umwelt-transformative.

Vim changes how you perceive text as a structured, navigable space. Lisp reveals code-as-data and makes you see programs as transformable structures. Haskell's type system creates new categories of thought about correctness, composition, and effects.

These aren't just new skills - they're new sensory-cognitive modalities. You literally cannot "unsee" monadic patterns or homoiconicity once internalized. They become part of your computational umwelt, shaping what problems you notice, what solutions seem natural, and even how you conceptualize everyday processes outside programming.

It's similar to how learning music theory changes how you hear songs, or how learning a tonal language might affect how you perceive pitch. The tools become part of your extended cognition, restructuring your problem-space perception.

When a Lisper says "code is data" they're not just stating a fact - they're describing a lived perceptual reality where parentheses dissolve into tree structures and programs become sculptable material. When a Haskeller mentions "following the types" they're describing an actual sensory-like experience of being guided through problem space by type constraints.

This creates a profound pedagogical challenge: you can explain the mechanics of monads endlessly, but until someone has that "aha" moment where they start thinking monadically, they don't really get it. It's like trying to explain color to someone who's never seen, or echolocation to someone without that sense. That's why who's never given a truthful and heartfelt attempt to understand Lisp, often never gets it.

The umwelt shift is precisely what makes these tools powerful - they're not just different syntax but different ways of being-in-computational-world. And like the bat's echolocation, once you're inside that experiential framework, it seems impossible that others can't "hear" the elegant shape of a well-typed program.

There are other umwelt-transforming examples, like: debugging with time-travel/reversible debuggers, using pure concatenative languages, logic programming - Datalog/Prolog, array programming, constraint solvers - SAT/SMT, etc.

The point I'm trying to make - don't try to "understand" the cons and pros of being a bat, try to "be a bat", that would allow you to see the world differently.

He anticipated an AI problem decades early. Replace “bat” with “LLM” or “alien intelligence,” and the paper reads like a warning: describing behavior and mechanisms might never reveal the inner feel, if there is one, to outsiders.

I think I wrote a whole book around this. :)) Feel free to reach out at theillusionengine@gmail.com for a draft :) https://illusionengine.xyz/ :)

> Nagel asserts that "an organism has conscious mental states if and only if there is something that it is like to be that organism—something it is like for the organism."

Struggling to make sense of this sentence.

The fact that we can't bridge subjective and objective descriptions without hand-waving probably says more about the limits of human concepts than about bats

Daniel Dennett was the only good part of the "New Atheism" movement. May he rest in peace.

Science studies the physical and measurable. Consciousness isn’t physical or measurable. That’s why the “hard problem” sits outside what science, by definition, can explain.

[flagged]

As Disney almost wrote:

Everybody wants to be a bat Cause noone but a bat really knows where it's at

I'm going to ignore the issues of mind/body dualism since they are orthogonal to the argument I want to make about Nagel's bat.

The short version is that if we can approximate the sensory experience and the motor experience of an organism, and we can successively refine that approximation as measured by similarity in behavior between bat and man-bad, then I would argue that we can in fact imagine what it is like to be a bat.

In short, it is a Chinese Bat Room argument. If you put a human controlling a robot bat and a bat in two boxes and then ask someone to determine which is the human and which is the bat, when science can no longer tell the difference (because we have refined the human/bat interface sufficiently) you can ask the human controlling the robot bat to write down their experience and it would be strikingly similar to what the bat would say if we could teach it English.

The bat case is actually easier than one might suppose, similarly say, a jumping spider, because we can translate their sensory inputs to our nervous system and if we tune our reward system and motor system so that we can get even an approximate set of inputs and similar set of actuators, then we can experience what it is like to be a bat.

Further, if I improve the fidelity of the experimental man-bat simulation rig, the experience will likewise converge. While we will not be able to truly be a bat since that is asymptotically mutually exclusive with our biology, the fact that we can build systems that allow progressive approach to bat sensory motor experience means that we actually do have the ability to image the experience of other beings. That is, our experiences are converging and differ only due to our lack of our technical ability to overcome the limitations of our biological differences.

The harder case is when we literally don't have the molecule that is used to detect something, as in the tetrachormat case. That said one of my friends has always wanted to find a way to do an experiment where a trichromat can somehow have the new photo receptor expressed in one eye and see what happens.

The general argument about why we would expect something similar to happen should the technical hurdles be overcome is because basically all nervous systems wire themselves up by learning. Therefore, as long as the input and output ranges can be mapped to something that a human can learn, then a human nervous system should likewise converge to be able to sense and produce those inputs and outputs (modulo certain critical periods in neural development, though even those can be overcome, e.g. language acquisition by slowing down speech for adults).

Some technical hurdle examples. Converting a trichromat into a tetrachormat by crispering someone's left eye. Learning dolphin by slowing down dolphin speech in time while also providing a way for humans to produce dolphin high frequency speech via some transform on the human orofacial vocal system. There are limitations when we can't literally dilate time, but I supposed if we are going all the way, we can accelerate the human to the fraction of the speed of light that will compensate for the fact that the human motor system can't quite operate fast enough to allow a rapid fire conversation with a dolphin.

Can we just all admit there has basically been no real progress made to the mind-body problem. They all rest on metaphysical axioms of which no one has any proof of. Physicalism is about as plausible as solipsism.

Exhibit a

> Nagel begins by assuming that "conscious experience is a widespread phenomenon" present in many animals (particularly mammals), even though it is "difficult to say [...] what provides evidence of it".

Answer: You are a creature of the night, terrible, able to strike terror into a superstitious, cowardly lot.

Douglas Hofstadter wrote an essay about this essay in the book “The Mind’s I” which I thoroughly enjoyed reading even if a lot of it is beyond me. There’s a somewhat janky OCR version here http://themindi.blogspot.com/2007/02/chapter-24-what-is-it-l...

Classic Hofstadter, he introduces a concept called a “Be-Able Thing” (BAT for short)

It's not like anything, a bat has no sense of self or personal history, it operates on instinct without a personal, reflective self. A bat having consciousness is as relevant as whether a sonar does.

What is it like to be another person?