Research and ethical questions in arthropod experience of "pain"

Pedant time: arthropod consciousness has not been disproven; https://www.researchgate.net/publication/336069068_Ethics_in_entomology

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I don’t remember exactly how I put it, but I believe what I actually said is there is very good reason to believe that insects did not feel pain. I stand by that, and the opinion paper you link to doesn’t go into the science or philosophy of insect pain. I don’t want to derail this thread with that conversation, but I’ll just mention one thing- insects don’t seem to care one bit to prevent their wounds from getting further damage. They just keep chugging along as if nothing had happened. In fact, orthopterans (crickets, grasshoppers, etc) have been observed cleaning themselves after a major injury, and when they get to their intestines (which are hanging out due to the injury), they actually start eating them. I saw that in a documentary once, it’s pretty gross. If that’s not a very good reason to believe they don’t experience pain, I don’t know what is :P

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I am well aware that many arthropod taxa seem unaware of their status after severe body damage; as for the paper I know it does not visit the neurobiology of insect perception but it cites at least one which does.

In amy case I do not wish to derail the conversation either but I have seen a few other papers mentioning learning and long-term memory of injury-avoidance behaviors, possibly suggesting that cryptic discomfort-qualia may occur even when no behavioral stress is visible.

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Yah… hard to accept that insects do not feel “pain”. My scientist neighbor (different field) said worms do not feel pain; that they do not have the neurological pathways that conduct pain signals. So, I asked (drawing on childhood memories of fishing with worms as bait), then why do they writhe (seemingly in pain) when you put them on a hook? The answer was a shrug that day, ‘it knew something bad was happening’.

So, I guess, define “pain’.

I wondered, if not pain pathways, then what? Being held captive in one spot? I thought not, as I could hold a worm in my hand and it did not act stressed at all, but when it was applied to a hook… then it definitely wriggled in a way that suggested much distress to me.

Sorry if this goes too far on a tangent from the original post. I am not sure this isn’t an ugly side of human perceptions of nature, tho.

I do try to view predation as the “circle of life”, though I also would have been disturbed by a pet following it’s predatory instincts against wildlife.

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I’ll reply in a PM to not derail the thread, and we could always start a new thread if you’d like.

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Sure it will writhe, that’s the reflex, they do quite the same when you just take them in hand, they do have feelings, in biological sense, not pain, and well, some are getting separated with shovels and do nothing, just keep going where they were, so it’s far from vertebrates.
Pain is easy to define in that case, it’s what make the organism suffer, what invertebrates feel is just a physical interaction, they’re not suffering.

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New thread vote! (or just voting to continue this aspect of conversation)
I think this is a really interesting debate - also heard similar tales quoted with cockroaches.
Hot topic for me atm, so, interesting to see this paper @coniontises, thanks for sharing…

I´m particularly interested in how this relates to perceptions of robotics + crossover…
Like the horrifying quote @bobwolski mentioned above from Descartes - ‘Gentleman, ignore the screams, they are merely the creakings of a machine.’ Powerful stuff.

Maybe we can agree with some of what @melodi_96 without stripping them entirely of sentience…but new lines have to be drawn… if we can simulate this with robotics, as we so easily can… then these arguments make me feel very uneasy.

We can also simulate realistic vertebrate pain and suffering with robotics. Pleo torture videos good example of this. Visible suffering can in some sense be argued to be an illusion as much as the opposite.

I don’t think there is anything “easy” to define around any of this without falling back to a human-centred POV around concepts of suffering itself, etc.

If I was brain dead, would it be ok to cut off my hand?

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https://www.discovermagazine.com/mind/the-colorful-case-of-the-philosophical-zombie

(you may also find this of interest, qualia are weird and thinking about them too much scares me though so I’ll be seeing myself out)

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I remember a zoology prac. Dipping earthworms in salty water. Until the salt concentration killed them. They tied themselves in knots. Even the memory, is painful, to me.

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Perceptions of inverts seem so much more about silence and scale than anything else.
If only worms could scream …

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Interesting! Not heard of the p-zombie concept before.

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I’ll just post my message to teellbee, since I already wrote it and copying/pasting is easy enough, but I’ll step out of the conversation after that.

So, I asked (drawing on childhood memories of fishing with worms as bait), then why do they writhe (seemingly in pain) when you put them on a hook?

Well, there’s a difference between pain and reacting to noxious stimuli. Worms, insects, plants, single-celled organisms such as cilliates, fungi, and even bacteria (in other words, everything alive) all have sensors and receptors of some kind or another that allow them to react to negative stimuli. Some move away, others build walls around something (such as scar tissue), they may secrete things, bioluminesce, etc. That doesn’t they’re actually experiencing pain though, and one example is in your own body. Have you ever had some sort of small injury that you didn’t notice until much later? I’ve often accidentally cut myself and not realized it until I noticed a red line on my finger. The same kinds of things happen inside your body all the time too- maybe you drink bad milk, or get an infection. Your body certainly notices and starts performing sometimes extremely complex things (it “writhes”) without any kind of conscious awareness on your part.

So, I guess, define “pain’.

Pain, in my view, is the unpleasant conscious experience that something is physically wrong with your your own body. There are lots of other kinds of experiences that people call “pain” (losing a loved one, for example), but for the purposes of this discussion I think it’s best to use a narrow definition instead of conflating a huge number of emotions (sadness, loss, isolation, depression, hopelessness, etc) into a single label.

I wondered, if not pain pathways, then what? Being held captive in one spot? I thought not, as I could hold a worm in my hand and it did not act stressed at all, but when it was applied to a hook… then it definitely wriggled in a way that suggested much distress to me.

It’s also worth noting that there are different levels of reactions to bad stimuli, since there are different levels of negativity when it comes to stimuli. Simply being held is not necessarily a life-threatening event, so it wouldn’t make evolutionary sense for the worm to waste too much energy in trying to escape. Getting a hook jabbed through your body is a lot worse, so the reaction that has evolved to deal with such situations is much greater- it makes sense to spend a lot of energy to try to escape that situation.

Of course, it is still possible that a worm feels pain, just like it is possible that your epithelial cells feel excruciating pain when they are killed by your immune system cells to contain an infection… but I don’t think that’s very likely. That has to do with evolution and the reasons the experience of pain evolved, but I’ll leave it there for now. I tend to ramble, and this message is already pretty long as it is :P

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Some invertebrates do suffer. In the UK researchers are required by law to use some sort of anesthetic if they are going to do any vivisection on octopuses, because octopuses are considered to feel pain and suffer distress.

I think a lot of us are overly influenced by Descartes’s views.

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The majority opinion of this and the original thread I started seems to be that humans see the world too naively, too ‘compassionately’, we see injustice where there is none. Nature is neither good nor bad.
It is just a valueless process. It’s all the yin and yang of nature. So are we supposed to be on Descartes side or not? On the one hand it seems yes, we should be. The predator dominates the weaker prey. Humans experiment on animals because we can, we’re stronger. That’s the natural reality of things. We want to learn things. I don’t think Descartes was maliciously killing an animal for fun. I’m sure it was in the interest of science.

If were not ‘supposed’ to be on Descartes side, then what does that mean? If we were there, we would have said, ‘No, you’re wrong, Rene. We think it’s terrible to eviscerate a live dog. And we should not suppress our spontaneous feelings of empathy.’

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I don’t know if this is controversial (though it certainly was in disagreement with a lot of my peers in college), but I don’t think whether or not an organism feels pain/is sentient/is conscious should matter at all when determining ethics with how organisms are to be treated.

For one, most studies aimed at determining whether an animal feels pain are limited by methodologies designed by humans and interpreted from a human lens. To test whether a fish or insect “feels” something based on criteria designed for rhesus monkeys and mice when both of the former have very different neural anatomy seems like a false equivalency. For a long time it was assumed that primates were the only animals to have complex neural anatomy and thoughts because of these oversights, or that fish were incapable of feeling pain. Fallacies like this, though less common, still persist in both professional and public spheres.

Additionally, whether insects and other arthropods feel pain or not really seems trivial because natural selection clearly has created conditions where arthropods strive to avoid things that may harm them or cause them premature death (e.g. predation, rushing water, a rival male). This is something observable in all successful, mobile animals, from bison to earthworms. Anyone who has observed a beehive or colony of fiddler crabs could attest to this, and a lot of literature exists to support this notion. Whether what they perceive can accurately be defined as “pain” is irrelevant.

My philosophy is this: if it is alive, it is of moral consideration. It’s sentience or perception of pain does not matter at all.

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Don’t tell me that, just last week I was writing an essay about 3R principle and animal laws, so I know tht not all invertebrates are the same.

I agree with much of this!

I guess that the argument for sentience has been crucial in passing laws for animal rights though for example, as Susan mentioned…so I guess, like it or not, we have to find a way to debate and define what is of moral consideration… and how we apply these considerations to mankind’s existence … in order to overcome those who are against affording rights to other beings.

I think this will all become a lot more complex soon also, the more robotics mimic the natural world and the less we can differentiate between the two. Your philosophy would have to argue for what it means to be alive…even if it steps around the question of pain itself.

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“it is still possible that a worm feels pain, just like it is possible that your epithelial cells feel excruciating pain when they are killed by your immune system cells to contain an infection… but I don’t think that’s very likely. That has to do with evolution and the reasons the experience of pain evolved”

oh do finish…I’m curious to hear the end of this part of your argument… what might be the reasons to believe a sense of pain evolved in humans but not other beings?

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I am not sure if there is a technical definition to describe “pain”, but I interpret “physical pain” as a feeling in response to harmful, cell-damaging stimulus that informs the organism that something is wrong, the body is in danger, and something should be done in response (e.g. move away from the flame, return to the sea, rest the arm where the muscles are damaged, stop running to relieve oneself, etc.).

I mean this with the upmost respect and I am curious to hear your response, but to suggest that the most conservative assertion to make is that an organism cannot experience pain unless explicitly demonstrated (especially a mobile, multicellular animal like an earthworm, which is far more complex than epithelial cells and has been documented to recoil in the presence of negative stimulus) does not seem rationale. For me, it seems far more conservative to assume that all mobile animals can feel pain unless demonstrated otherwise. Mobility grants organisms a huge evolutionary advantage over sedentary beings not only in resource accessibility and the ability to search-out mates, but also in avoiding destructive stimulus. It is fundamental.

Wow, I wasn’t even considering implications for artificial intelligence or bio-mimicry. When I was little these seemed like such far-removed, sci-fi concepts but I guess this is something to legitimately consider within our lifetimes. I wasn’t even thinking about that. I was more so thinking about trees and coral, which I have gotten into arguments about with people who weren’t particularly biophilic. They did not think either warranted any kind of conservation or legislative protection for their own merits, but because they are utilized by more sentient beings. I’m inclined to think that the lives and conservation of plants matter because they are alive. I have also been in lectures about animal ethics and our relationship with non-human animals, and I was disappointed that my classmates - who were largely animal rights activists, vegans, or biologists - became incredibly apathetic when the topic of discourse shifted from cats and dogs to fish or insects. I’m paraphrasing something I read from Dr. Douglas H. Chadwick, but from a philosophical and spiritual perspective rooted in evolutionary thinking, all life are part of “our greater selves”. They are a part of us and warrant moral consideration for that alone.

I know the role that a sentient gradient plays in animal right laws, but that too is a fallacy in my eyes. Too many people and organizations use this to justify the mistreatment of animals because they are considered too cognitively simplistic to warrant protection or rights, even though how we traditionally interpret sentience is from a human bias. Dog meat was recently outlawed in the United States, even though horses, cattle, pigs, sheep, and chickens are not too far removed from them on a sentient gradient (and in fact, pigs are potentially more cognitively complex animals). They are just culturally seen as inferior or stupid, which I argue has a greater baring on animal rights than any study on sentience. Seems hypocritical. There are almost no meaningful laws for the ethical treatment of fish, despite being farmed in mass in horrid conditions and being demonstrated to perceive pain.

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davidenrique …I appreciate how well you expressed some complex concepts in ways that made this position (lower beings don’t perceive pain) “conceptualize-able”. But, my sense is that such lower invertebrates do experience pain in a way that goes beyond a mere reaction to “unpleasant” stimuli. I realize that sounds sort of unscientific, but I figure we may not understand the actual neurological/biological pathways and functions of invertebrates that well yet…

Well, I’ve been noodling about this and the only thing that aligns as being noxious but not painful (at moment) is the horrific smell of a decomposing, um, mammal. Not exactly pain like a burn, but it makes me heave. I think I’d avoid it just as vigorously as I’d avoid hitting my thumb with a hammer. So, very noxious, very strong reaction, yet not what I’d call pain even though it causes a strong physical reaction. So, maybe strongly a noxious event is as bad as strongly painful one to this organism.

Pain, in my view, is the unpleasant conscious experience that something is physically wrong with your your own body.

Hmm…, a worm writhing on a hook strikes me as a good example of some consciousness that something is physically wrong with its own body.

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