Of course it is real. When I feel pain from an injury, the injury is very real, my pain sensor's signals are real and my brain's interpretation of those signals is real, and my behavior of trying to avoid further injury is real.

> Again, is there any reliable source for that other than a whole book that probably doesn't even talk about what you claim? If it is in the book, can you give a detailed reference where to find it? And if so, does the book provide references to research underpinning those claims?

Lisa Barrett is a very famous professor of neuroscience, so sure there is a lot of research in that book :) Here is a short video where she explains it https://www.youtube.com/watch?v=0QfCvIJRtE0 I also recommend her interviews with Lex Fridman.

She talks more about emotions as predictions, but we mean the same thing.

Here is a highly cited paper where she explains the theory: https://pubmed.ncbi.nlm.nih.gov/27798257/

> Or did you just come up with that on your own? It sounds absolutely ridiculous to me. Any attempt to "model" the experience is prone to fail by lack of evidence because pain is, by definition, subjective.

Your pain is very subjective yes, but that just means that it is created by your internal model of the world and yourself, which has a unique subjective perspective of the world.

> If you just search for the definitions of belief, emotion and pain, you will quickly find that their meanings are distinct. Claiming that pain is a belief is absurd.

These words are normally not used in the way I use them, but the point is that emotions are outputs of our model of ourselves. These outputs you can call beliefs, predictions or interpretations if you like.

> If a computer prints on the screen "I'm in pain", is it actually in pain?

Maybe. If you SMS me that you are in pain, are you in pain? "I'm in pain" is evidence of someone being in pain. But being in pain, the referent, is just being in pain. There's no additional indirection.

> If you are sedated with a memory blocker, and are then hurt, but you don't remember it afterward, were you actually in pain?

Yes.

> You want an explanation of the wrong "ground reality", you are discussing the wrong question, it's not "is pain" real.

No, this is an issue that was actually brought up.

> > maybe [...] you [...] [don't] actually feel pain

All reason is grounded in experience. If I know anything, it's the things that I experience directly. Pain is probably the most direct experience there is.

edit:

> It's all about the subjective experience of pain, and can a robot share in that? Can a person in a coma share in that? Can an animal?

Yes. No. Yes.

These are not difficult questions to answer... You're phrasing it like there's some kind of philosophical difficulty here, but I don't think there is. If you define pain as an aversive sensory experience, ie. a sensory experience that makes you wish it would stop (this definition covers disgust and discomfort as well, and I think that's valid), then it seems clear that anything that can form goals (and yes, a memory blocked sedated person can form goals, they just can't act on them) can experience pain. I think the objection to computers is just that we rely too much on our empathy to determine when something "is in pain". I think an NPC in a game that moves away from a fire is experiencing pain, even though its mind is extremely simple, just like an amoeba would when it avoids a harmful chemical. It doesn't have such a thing as a qualia of pain, maybe (I'm not convinced!) - but that's hardly necessary.

I feel we must overcome our distrust of functional descriptions. Pain is a functional pattern, and not a very complex one.

> And why ... if nociception is merely behavioral effects? ...

This is definitely not consistent with the definition I'm using. Rather, I'm using nociception to refer to the low level _physiological_ responses to damage (specifically the set of molecular pathways that are in some way organized as part of a larger systemic response to said damage).

The term pain can then be assigned to a particular qualia, leaving a few other phenomena on the levels in between the two. This makes nociception easy to speak and reason about and helps avoid some of the most confusing or apparently contradictory situations but otherwise leaves the higher level stuff (pain, motivation, various other qualia) as difficult to figure out as before.

In the case of complications related to anesthesia I'd say it's squarely in a grey area that the classification scheme I'm applying here doesn't handle as well. That's due partly to the line between physiology and psychology blurring at times, and partly to the (related) fuzziness of the term unconscious as it applies to an organism's biology.

Even when you're unconscious, a great deal of your nervous system still has to be functioning on some level in order to keep you alive. Since psychology arises from your nervous system, which is in turn made up of innumerable physiological effects, then it's not inconsistent with the definitions I'm using that we can observe nociceptive pathways resulting in changes to some of the higher level systems even if someone was unconscious while they were active.

> When Tanya decides to react to burning her hand on a stove by moving it away, is she really experiencing the exact same kind of nociception that you or I experience when we burn our hand on a stove and move it away?

I'd point out that (given the definition I've been using) we don't experience nociception but rather some higher level qualia that's downstream of it. Not knowing all that much about her case other than what appears in your article (ie pain insensitivity) I honestly have no idea. She obviously doesn't experience what any of us would describe as pain. Beyond that, how can we know what qualia someone else experiences? If we assume her to be otherwise identical to us then I suppose it would depend on exactly where in the pathway that runs from nociception to pain response her genetic abnormality manifested.

> ... despite the lack of qualia, look like learning processes about avoiding damage.

Precisely! As I'm modeling it, useful (evolutionarily) nociceptive pathways can give rise to avoidance or learning processes in any way whatsoever. All that's required is that their presence increase organism fitness!

In the case of many simpler organisms I suspect there might not be any qualia or learning whatsoever (and thus no loss function, bi-level or otherwise, on the level of an individual organism). Rather, nociceptive pathways might simply trigger some set of immediate, hard coded, higher level responses. (Consider C. elegans in particular and I think this will make a lot of sense.)

Up organism complexity a bit and you might encounter learning in the form of something resembling a simple state machine. In other words, employing nociceptive pathways to form a very basic set of associations between specific environmental conditions and some sort of danger or avoidance response. This could allow preemptively avoiding something that caused damage (and thus lowered fitness) in the past. (This might or might not be bi-level depending on what other learning pathways, if any, it interacted with.)

Under such a model, it's only when you make it up to incredibly complex organisms whose behavior is governed (to at least some extent) by higher level reasoning that you might encounter things we could identify as psychology, qualia, or pain. This is where bi-level losses seem to become particularly important and also where things rapidly become incredibly complicated to model.

That being said, it seems to me that a hardwired avoidance response (ie an outer loss) is likely only necessary for initial bootstrapping (in the case of sufficiently well educated humans) or in an organism where higher level reasoning is present (and thus driving behavior) but not sufficiently advanced. For example, it seems at least plausible that Tanya might have been fine if only there were some way to imbue her with a well developed understanding of the world. Then again, maybe not - it's quite possible that other internal processes have developed a dependence on the pain response being present, and so ripping it out without doing any other remodeling might well result in a "pain sized hole" and a nonviable organism.

Interesting. A couple of days ago I was washing dishes and the water was too hot, so I almost burnt my hand--or so I thought--by putting it directly under the faucet by accident. Nonetheless, I started playing with it for a while: how long could I keep it there? I realized that if I put my hand under it, whenever I gave in to fear, the pain got unbearable, as if a switch had been turned on.

I think that's why expert meditators can handle pain better. Also, meditation and yoga reduce the right amygdala's volume [0], which processes fear and negative emotions.

[0] https://www.psypost.org/2019/08/meditation-and-yoga-practice....

I don't know if I understand what you mean. I agree that we evolved to have pain for a very important reason and that it's extremely useful to react to it differently than other sensations. But does a relatively light, non-life-threatening pain need to take so much of your attention once you realize you're not in danger?

>Am I understanding your phrasing correctly? That, if you're not afraid of death, then physical pain won't bother you at all? I don't think that's right.

I'm not saying submit to it willingly, or not to escape if it's possible, but otherwise yes. To me it's the struggling against the pain that causes suffering.

>Another q: What kind of benefit/enlightenment do you achieve by leaning into the pain of a stubbed toe? Why lean in to it and pretend that you

The difference is between the unpleasant, subjective experience (qualia) and the electrical signals indicating physical damage.

A car has sensors that detect physical damage, yet it doesn't feel pain in the way that humans do. The question is, where on that spectrum bacteria, ants, and fish lie.

> Have you seen ants writhe around after being crushed or dismembered? They definitely feel pain.

Have you seen a car deploy its airbags and notify emergency services after a crash? And yet, they definitely don't feel pain. Visible reaction to a negative stimulus is neither a sufficient nor a necessary precondition for someone or something to feel pain.

I agree. However, my response if I intentionally don't over-think it, is "well she learns from a single example because that experience was painful and she wants to minimize pain."

Granted that's true as much as it is facile, but I do wonder if it hints at what the next frontier will consist of. A thermometer will happily keep reading out the temperature of a room heater until its physical form is damaged. A human child has a concept of pain to dissuade behaviors that lead to harm (in theory) (this is obviously simplified).

Actually nociceptive pain is by definition not in the brain and is fundamentally somatic. However somehow it is privileged by society: it’s “real” pain while those others are “all in your head”.

The sad thing is that the scientist is validating these phenomena yet the critics don’t understand that.

That can't be emphasized enough in this debate. In short: if you arrived at some magical scan or test that indicated the presence, by degree of nerve stimulation of hand-over-a-hot-flame-type pain, and only prescribed painkillers to people over some threshold, you'd still be both excluding people who were personally suffering as much or more as those who made the cut, and including people who did not experience the same discomfort.

The human sensorium has a lot of experiences in common, but also a ton of differences.

How are they different? Pain is a negative stimulus response that allows us to know whether something is causing damage to our body.

> We know we feel pain. We can guess that organisms with similar brain architectures are feeling pain.

How does feeling pain have anything to do with a brain's architecture? It has more to do with nerves... block a nerve's functioning, and you don't feel pain. Also, pain can be psychosomatic.

> Ants keep doing their job even after fatal damage. If they feel something, it is not anything like our pain.

Have you seen ants writhe around after being crushed or dismembered? They definitely feel pain.

> So it is not obvious that our feeling of pain is universal.

Depends on your definition of pain, doesn't it?

This seems exactly backwards to me. The visceral sensation of pain exists precisely in order to bypass your conscious decision-making. When you're hurting, your body doesn't want you to start weighing the pros and cons of various courses of action, it wants you to deal with the injury right now. That is the reason that pain feels very different -- much more urgent and harder to ignore -- than (say) getting a text message informing you that you have been hurt.

no. Pain has basic objective component, basic common denominator - it is the specific reaction of nervous system, specific set and intensity of signals going through it in reaction to tissue damage. More complex nervous systems build more complex constructs on top of that foundation, like the expectation of pain, memory of pain, etc... and many of that additional constructs are subjective in nature, no argument here.

>For example, if I got hit by a car and ended up brain dead, it's intuitive to claim that I would no longer be able to experience pain even if you decided to cut off one of my limbs.

does your amygdala still function - fully "brain dead" would mean no, so no pain.

geezerjay made the point that the ability to experience pain is a useful survival trait, so we should expect it to be widespread.

Filling in some gaps in your argument (please correct me if I get them wrong), you're arguing that there are other negative stimuli that could have equivalent usefulness and therefore pain itself is not beneficial for optimising survival. Any equivalent stimulus would do.

Since there's no way to tell what anyone feels, the entire subjective experience of pain can only be defined by looking at analogous physiology and response. We can look at things like whether a species has nociception, whether their nociception system interacts with their central nervous system, whether they respond to painkillers, how they make choices about negative stimuli, adaptive avoidance, etc.

To have the same survival value, your 'negative stimuli' must be indistinguishable from pain. They have to be because you imply they illicit the same response in the same situation, and (barring species that are clearly missing key parts of nociception) the response is all we can look at.

Your argument seems to rest on redefining the (admittedly vague) biological understanding of pain to mean a unspecified subset of 'things that are indistiguishable from pain'... which I don't buy as being anything other than an existential conundrum and in my opinion doesn't seem like a basis to call geezerjay's comment "over-simplistic".

The contrast was the idea I was putting forward. Pain defines pleasure if that makes sense and visa versa.

> Pain is a signal from your body telling you something is going awry.

I would say it is a signal from the mind (emotions can be painful) but I agree with your general point.

> Now if you are talking about effort that's something else. Your body and mind are normally equipped for effort and will reward you according to the result of this effort.

Cue, craving, response, reward. Is the craving not painful? If the response requires an unanticipated level of effort is that not painful?

Do you see how it isn't so much about avoiding pain and more about choosing what cues you respond to and understanding what pain is unavoidable and/or what pain you are willing to endure.

Rather I see it as splitting along an intuitive boundary - namely a whole host of low level biological responses (seriously there's a lot) versus higher level psychological (ie perceptive, conscious, whatever) phenomena. This seems particularly meaningful to me in part because most low level multicellular organisms that otherwise lack anything resembling emotion or psychology of any sort still possess (often highly conserved) analogous pathways.

My understanding is of nociception being a biological phenomenon that can be measured by proxy via behavior. It's important to note that the behavior itself isn't the nociception but rather a downstream response to it. That might sound like nitpicking but it's important because nociceptive responses can and do occur (and are of clinical significance) in patients who have lost consciousness. (At absolute minimum it seems weird to me to talk about an unconscious patient experiencing pain. Surely we benefit from being able to draw a distinction here?)

So (for example) the mouse tail flick test is a means of quantifying the nociceptive response which presumably also causes the rodents some mild pain. In fact it's (presumably) pain that actually results in the behavior that's measured but we can't quantify it on account of (at minimum) being unable to meaningfully communicate with them. Compare this to a physician collecting periodic "pain level" survey responses from a postoperative patient.

Semi-related thought: The term nociception allows avoiding confusing turns of phrase such as "painful pain" and "nonpainful pain". Surely the apparently contradictory term "nonpainful pain" should alone be sufficient evidence that there are important distinctions to be made here (and hence justify the additional terminology)?

Another semi-related thought: I find things much easier to reason about once they're "stacked" like this. Otherwise, trying to make sense of nonpainful pain, or the C. elegans thermal response, or the physiological responses of unconscious patients is downright confusing to me. Modeling it as "damage -> nociception (ie sensing) -> pain (ie psychology) -> response (ie behavior)" is much more intuitive to me. Importantly, it provides a framework for differentiating between cases that have more or less of a psychological response involved in mediating any behavioral ones, as well as allowing for cases that exhibit only physiological responses (ie nothing psychological or behavioral). (Or perhaps it just helps scientists sleep at night after they throw a few hundred plates with thousands of C. elegans each into the autoclave?)

The parent comment wasn't dismissing it. Quite the contrary. You, however, do seem to be dismissing it, by saying "nothing but anxiety". Anxiety is very real.

>Would you similarly dismiss phantom pain and prescribe anti-depressants and CBT?

Pain can quite often be caused/exacerbated by psychological factors. Perhaps you should google "central sensitization". The parts of the brain that registers pain (the insular cortex and ACC) are also responsible for attaching emotional feelings to pain. In some cases (e.g. fibromyalgia) the pain persists in the absence of any physical pain signal.

To address this specific point (not the rest of your comment, which I largely agree with): this is in line with the "old" bio-medical model of pain, and not up to date with the modern bio-psycho-social model of pain. In many cases, the biological insult to tissues will fully heal far in advance of pain subsidence, or conversely will heal long after pain subsidence. The point being that a pain experience is not an accurate indicator of the state of one's tissues.

For a primer on this more modern model of pain experiences, please give this excellent video a watch: https://www.youtube.com/watch?v=lCF1_Fs00nM

That makes more sense than I was expecting. In particular, pain must be felt in the brain. That is, my body can be suffering some trauma, but if the nerve signals don't make it to the brain, or the brain doesn't interpret them as pain, then I don't feel pain. (This is true of third-degree burns - they don't hurt very much, because the nerves got destroyed, so you don't feel how bad the burn is.)

But if the body isn't under (known) trauma, but the patient is experiencing pain, maybe the brain is a reasonable place to look...

I don't think the distinction between behavior carried out by reflex networks and behavior carried out by planning involving mental models is arbitrary. We have no reason to think reflex networks involve experience whereas we do have reason to think behavior involving mental models does. So it seems like this distinction is the critical distinction in terms of determining if some organism experiences pain.

>Anyway, avoidance is assumed to already happen as a separate system.

You're projecting more onto the term "avoidance" than is warranted, and you haven't defended your reading of the term. I take something like the withdraw reflex as an example of an avoidance behavior. Clearly you don't, but since your argument rests on your different understanding of the term, and your assumption that the authors of the article intend your reading of the term, its the key disagreement and deserves more attention.

Continuing the quote from the article you started "...In non-humans, we call this sense ‘nociception’, the sense that detects potentially harmful stimuli like heat, cold, or physical injury". So it doesn't seem like the authors are intending to reference predictive behavior, but simply protective behavior in response to noxious sensory perceptions, what you called reactive behavior.