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.
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.
“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.
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).
Nagel's "What is it like to be a bat?" assumes that bats are conscious, and that the question of what is the subjective experience of being a bat (e.g. what does the sense of echolocation feel like) is therefore a meaningful question to ask.
The author inventing "batfished" also believes bats to be conscious, so it seems a very poorly conceived word, and anyways unnecessary since anthropomorphize works just fine... "You've just gaslighted yourself by anthropomorphizing the AI".
From the point of view of a LLM, words are everything. We have hands, bats have echolocation, and LLMs have words, just words. How does a LLM feel when two words match perfectly? Are they hurt by typos?
It may feel silly to give LLMs consciousness, I mean, we know how they work, this is just a bunch of matrix operations. But does it mean it is not conscious? Do things stop being conscious once we understand them? For me, consciousness is like a religious belief. It is unfalsifiable, unscientific, we don't even have a precise definition, but it is something we feel deep inside of us, and it guides our moral choices.
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.
That's the magic answer. It's a/the hard problem, but permeable to inquiry. The top neuroscience research into consciousness however doesn't seem like this kind of inquiry Dennett is referencing.
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.”
That’s called meta cognition (what humans do) not subjective experience - which is the feeling of what happens and sets animal or agentic creatures apart from rocks (not sure about plants)
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.
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".
>Can we just all admit there has basically been no real progress made to the mind-body problem.
I think we've made extraordinary progress on things like brain to machine interfaces, and demonstrating that something much like human thought can be approximated according to computational principles.
I do think some sort of theoretical bedrock is necessary to explain to "something there's like to be" quality, but I think it would be obtuse to brush aside the rather extraordinary infiltrations into the black box of consciousness that we've made thus far, even if it's all been knowing more about it from the outside. There's a real problem that remains unpenetrated but as has been noted elsewhere in this thread, it is a nebulous concept, and perhaps one of the most difficult and important research questions, and I think nothing other than ordinary humility is necessary to explain the limit an extent to which we understand it thus far.
>"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.
The “something” here refers to inner experience (something similar to Kantian “aperception”.
The tricky bit is that “to be” is not an ordinary verb like fly, eat, or echo-locate. And “‘being an organism’” is — in the context of the paper — about subjective experience (subjective to everything except the organism.
To put it another way, the language game Nagel plays follows the conventions of language games played in post-war English language analytic philosophy. One of those conventions is awareness of Wittgenstein’s “philosophical problem”: language is a context sensitive agreement within a community…
…sure you may find fault with Wittgenstein and often there are uncomfortable epistemological implications for Modernists, Aristotelians, Positivists and such…then again that’s true of Kant.
Anyway, what the language-game model gives philosophical discourse is a way of dealing with or better avoiding Carnapian psuedo-problems arising from an insistence that the use of a word in one context applies to a context where the word is used differently…Carnap’s Logical Structure of the World pre-dates Wittgenstein’s Philosophical Investigations by about 25 years.
Nagel's question "What is it like to be a bat?" is about the sensory qualia of a bat, assuming it has consciousness and ability to experience quales, which he assumes it does.
The question is not "What would it be like (i.e. be similar to) to be a bat?" which seems to be the strawman you are responding to.
That particular phrasing happened to catch on, but I don't think it's essential to any of the arguments. How would you phrase the distinction between objects that are conscious and objects that aren't? Or are you saying that that distinction is just a verbal trick?
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)
The Ethiops say that their gods are flat-nosed and black, While the Thracians say that theirs have blue eyes and red hair. “If oxen and horses and lions had hands and were able to draw with their hands and do the same things as men, horses would draw the shapes of gods to look like horses and oxen would draw them to look like oxen, and each would make the gods' bodies have the same shape as they themselves had.
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.
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?
>Anything that is able to be measured is able to experience.
I was quite liking this explanation but you lost me here. I very strongly agree with your opening, and I think it's the key to everything. I think everyone insisting on a categorical divide runs into impossible problems.
And a good explanation of consciousness has to take the hard problem seriously, but doesn't have to agree that subjective and objective, or first person in third person or whatever you want to call them, are irreducibly distinct categories. But I think it makes more sense to say that some subset of all of the objective stuff out there is simultaneously subjective, rather than saying that all stuff at all times is both objective and subjective. I don't think an apple experiences gravity the way a mind experiences a conscious state, but I do think the through line of understanding them both as importantly physical in the same sense is key to tying physical reality to explanation of conscious states.
> 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."
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.
It makes sense given that we are just receiving light waves instead of sound. Light waves contain way more information but your brain would still come up with some kind of "visualization" based on the info. I didn't listen to the program but he might just see blobs of varying sizes instead of any kind of detailed image.
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?
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.
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."
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.
55 comments
[ 2.8 ms ] story [ 61.6 ms ] thread— 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.
https://partiallyexaminedlife.com/2025/06/30/what-is-it-like...
The author inventing "batfished" also believes bats to be conscious, so it seems a very poorly conceived word, and anyways unnecessary since anthropomorphize works just fine... "You've just gaslighted yourself by anthropomorphizing the AI".
That's a question I actually asked myself.
From the point of view of a LLM, words are everything. We have hands, bats have echolocation, and LLMs have words, just words. How does a LLM feel when two words match perfectly? Are they hurt by typos?
It may feel silly to give LLMs consciousness, I mean, we know how they work, this is just a bunch of matrix operations. But does it mean it is not conscious? Do things stop being conscious once we understand them? For me, consciousness is like a religious belief. It is unfalsifiable, unscientific, we don't even have a precise definition, but it is something we feel deep inside of us, and it guides our moral choices.
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.
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.”
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.
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".
I think we've made extraordinary progress on things like brain to machine interfaces, and demonstrating that something much like human thought can be approximated according to computational principles.
I do think some sort of theoretical bedrock is necessary to explain to "something there's like to be" quality, but I think it would be obtuse to brush aside the rather extraordinary infiltrations into the black box of consciousness that we've made thus far, even if it's all been knowing more about it from the outside. There's a real problem that remains unpenetrated but as has been noted elsewhere in this thread, it is a nebulous concept, and perhaps one of the most difficult and important research questions, and I think nothing other than ordinary humility is necessary to explain the limit an extent to which we understand it thus far.
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.
The tricky bit is that “to be” is not an ordinary verb like fly, eat, or echo-locate. And “‘being an organism’” is — in the context of the paper — about subjective experience (subjective to everything except the organism.
To put it another way, the language game Nagel plays follows the conventions of language games played in post-war English language analytic philosophy. One of those conventions is awareness of Wittgenstein’s “philosophical problem”: language is a context sensitive agreement within a community…
…sure you may find fault with Wittgenstein and often there are uncomfortable epistemological implications for Modernists, Aristotelians, Positivists and such…then again that’s true of Kant.
Anyway, what the language-game model gives philosophical discourse is a way of dealing with or better avoiding Carnapian psuedo-problems arising from an insistence that the use of a word in one context applies to a context where the word is used differently…Carnap’s Logical Structure of the World pre-dates Wittgenstein’s Philosophical Investigations by about 25 years.
The question is not "What would it be like (i.e. be similar to) to be a bat?" which seems to be the strawman you are responding to.
"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)
- Xenophanes, ~500 BCE
<https://www.azquotes.com/author/38174-Xenophanes>
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 was quite liking this explanation but you lost me here. I very strongly agree with your opening, and I think it's the key to everything. I think everyone insisting on a categorical divide runs into impossible problems.
And a good explanation of consciousness has to take the hard problem seriously, but doesn't have to agree that subjective and objective, or first person in third person or whatever you want to call them, are irreducibly distinct categories. But I think it makes more sense to say that some subset of all of the objective stuff out there is simultaneously subjective, rather than saying that all stuff at all times is both objective and subjective. I don't think an apple experiences gravity the way a mind experiences a conscious state, but I do think the through line of understanding them both as importantly physical in the same sense is key to tying physical reality to explanation of conscious states.
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)
Struggling to make sense of this sentence.
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...
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
"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."