Did you read the article? It attempts to explain why verifying "pain" is difficult: simply reacting to a stimulus is an unacceptably low bar, unless you're living your life believing that all the plants you've eaten and the bacteria you've soaped off your hands were murdered, so they're attempting more subtle analysis to pull back the curtain on the inner states of animals, point being that the inner state is what's necessary for pain.
It's not terribly surprising, intuitively, that a large range of living things feel and remember pain.
The seeming clarity or obviousness doesn't mean it's not worthwhile to study it, test the assumption, prove or disprove, figure out what creatures are subject to it and to what extent, etc. I imagine we could learn a lot trying to explain it.
> How are they different? Pain is a negative stimulus response that allows us to know whether something is causing damage to our body.
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.
This surprised me. Nociception is the term you will find in the biological literature because we can't quantify how (for example) a mouse "feels" when it's tail is dipped in hot water but we can quantify the behavioral response and use it as a proxy for the underlying biological mechanism.
Once you separate the biological and psychological responses in this manner the reasoning seems (to me) to become much cleaner.
Without higher level reasoning, nociception just needs to trigger any learning response in order to achieve survival. That's an incredibly open ended requirement.
In the presence of higher level reasoning then, pain could be viewed as a secondary effect that in turn triggers some learning response. So if you have higher level reasoning you don't necessarily need pain, but you probably do need nociception plus some other robust downstream response for a reliable organism. (This seems to mostly match up with the observations about useful nonpainful pain in the article.)
> Negative stimulus reaction and pain are different things.
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.
Epistemic asymmetry. You can't even prove that the pain-behavior you observe me demonstrating reflects an internal experience that's anything like your experience of pain, so asking for "proof" that a fish's pain is actually painful isn't even an objectively meaningful question.
I’m a bit surprised by the number of comments here basically saying if we can’t logically prove that X feels pain, then it’s fine to do whatever with it, or that if we don’t know exactly where the line should be drawn, then there’s no line to be drawn at all.
Do you all always behave according to well-defined rules within a consistent logical system?
I don’t think you can prove to me that you or your pets feel pain, so what would be the logical consequence of that?
The argument that the existence of negative stimuli disproves the ubiquity of pain only holds if "response" is a single atomic thing, which it isn't. Animals don't respond in the same way to being prodded in the head as they do to being, say... eaten alive, so the existence of other forms of negative stimuli doesn't prevent you learning about pain responses.
For example, fish have been reasonably shown to feel pain by comparing their responses under painkillers to their natural responses.
Personally I don't think our experience of pain is universal, it'll be different with each combination of neurological and biochemical apparatus, but to me the idea that pain must somehow be proved rather than assumed in higher order is somewhat disturbing and indicitive of our continuing hunger for exceptionalism.
What bullshit - how does it hurting prove that pain is not just information? Just because the brain is hardwired to react to it in a certain way does not mean it is not simply information. You could easily program a robot that is incapable of pushing a needle into it's hand (provided there is a sensor there).
Disclaimer: I stopped reading the article after the description of the "experiment".
> It doesn't disprove it, it just demolishes that particular argument.
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".
> pain itself is predicated on its accurate coupling to injury, since the purpose of pain is inhibitory
> pain very much does indicate tissue damage
These statements are not supported by modern research. The bio-psycho-social model indicates that pain is a threat detection and deterrent mechanism, NOT a "status report" from the painful tissue to the brain. In other words, the brain is concerned that something might lead to physical trauma, yet none need to have taken place for pain to be generated.
There are certainly biological inputs to the "pain generator" function of the brain (like sensing a foreign object touching one's skin), but psychological factors/contexts and social factors/contexts can be equally strong inputs (and ultimately generate a significant pain experience without any, or with very little, biological input).
Think of the magnitude of pain response to a given situation as an indicator sitting somewhere on a spectrum between "benign" and "dangerous". The more psychologically threatened one feels, the more the pain response will be shifted toward the "dangerous" end (i.e. higher magnitude). The more socially threatened one feels, the more the pain response will be shifted toward the "dangerous" end.
Here is a somewhat contrived but favorite example of mine. One night, you wake up to go to the bathroom. In the dark, you unexpectedly step on your child's lego brick left on the floor, and it hurts immensely - it feels like the pegs are actually spikes! This is mainly because of how it has surprised you; the context is that it's dark, you expected the trip to the bathroom to be just a few simple steps, and (for sake of argument) have never stepped on a lego before. Your brain feels rather threatened by this surprising situation and generates a large pain response. Now, a night or two later, it happens again, and though it hurts it definitely isn't as bad. Another night or two later, it happens a third time, and barely hurts at all (you're basically to the point of expecting it now). I think we can agree that no tissue damage has really been done, and if pain was simply a state-of-tissue indicator then the magnitude of pain should have been the same each and every night. Additionally, if tissue damage need be present for pain to be present, why did it hurt at all?
Lastly, I'll note that lack of apparent examples != lack of evidence.
Good point. It is all deduction, and I guess that is what science is about: deduction, not proof.
Regardless of whether or not an entity X experiences pain, we can still objectively state that entity X responds negatively towards stimuli associated with the feeling of pain in ourselves.
While there is not a whole lot of substance in the article, it's not unreasonable to assume that insects are capable of nociception. Even single-celled organisms like amoebas can show an injury response, because it makes sense evolutionarily to be able to react to harmful environments. That insects produce some of the same neurochemicals as higher animals is also not surprising - these pathways have been evolving for a long time. Of course, they tend to grow in complexity with the rest of the organism.
What the article gets wrong, I believe, is the ethical dimension. I would make the argument that for an organism having nociceptors and pain responses is not enough to assume capacity for suffering as we know it (which granted is always a big caveat). I could write a program for a simple robot that shows a pain response. That's not enough.
The missing component here is a brain capable of suffering in a meaningful way. Personally, I suspect there is no convenient limit value for this as you go up the ladder of brain complexity. It's just one big muddy gradient. Where a person draws these lines is almost arbitrary: for example, I don't really care about the well-being of a moskito, but starting with spiders I feel increasingly guilty for not helping them when they're in trouble.
I dislike the title here: Pain isn't necessary. The path evolution took - why pain exists makes sense - but the author's statement in the title is absurd.
I can easily imagine a future where we have obsoleted pain as a communication channel. Pain is a neurological version of a healthcheck system and not even a particularly good one; it's slow, has no off or way to silence false reports, and lacks context. Pain doesn't tell you what the problem is; only that there is a problem. Any engineer who had to deal with such a low-bandwidth protocol would be complaining about it loudly.
Pain is not necessary. And I hope it is replaced soon.
> My understanding is of nociception being a biological phenomenon that can be measured by proxy via behavior...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?
It may be weird, but I think it's very valuable to have a taxonomy which lets you ask about kinds of pain which are not merely yoked to immediate verbalizable things. As you say, it is complex.
For example, if you thought 'unconscious pain' is a contradiction in terms, then what do you make of things like anesthesia awareness or the troubling long-term PTSD-like symptoms in some people who undergo anesthesia ( https://www.lesswrong.com/posts/wzj6WkudtrXQFqL8e/inverse-p-... )? That may be 'behavior' but they certainly are not classic indicators of pain. They are not like dipping a mouse's tail in hot water and observing its movement. They do, however, despite the lack of qualia, look like learning processes about avoiding damage.
And why do we apparently have consciously-perceived damage signals which can in fact motivate behavior (if the person chooses to) without the accompanying painful qualia, if nociception is merely behavioral effects? 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? It's the same behavior, after all.
I'm sure you can extend 'nociception' as a word to cover some but not all of these cases, but by that point, nociception needs the entire essay as a preface just to explain what one means by that, which is why I don't use it. It is a pointer to an entire theoretical & empirical apparatus the reader does not have. Anyone who already knows all that doesn't need to read the pain section at all as it's obvious why pain in humans is an example of bi-level losses.
> 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?
I think it was Steven Pinker who said he stopped doing animal experiments when he could no longer convince himself that hitting mice on the head with tiny hammers to give them brain damage was not the most evil thing he did...
>little human beings react to things which are known to be painful. Babies feeling pain is something that should be self-evident, shouldn't it
Perhaps this is just semantics, but I think "feeling pain" implies a higher level of cognition than simply reacting to things which are known to be painful. Like the classic toddler move of painting with their feces. They're obviously physically capable of smell but it just doesn't seem to register the same way.
“Babies feeling pain is something that should be self-evident, shouldn't it?”
I have yet to understand the historical underpinnings of this phenomenon, but as someone who deals with chronic pain, doctors don’t seem to be aware that people feel pain _in general_.
I’m being sort of facetious, but any chronic pain community is full to the brim with stories of various medical professionals being skeptical of patients’ pain reports or treating pain like it’s not a particularly important quality of life concern.
I have my own stories about this, of course, and some of them are pretty horrible.
It doesn’t surprise me, then, that we assumed at some point that infants don’t feel pain: after all, if we don’t take the pain of adult humans seriously, then why would we consider the pain of a creature who cannot even directly complain about it?
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