# Why shouldn't invertebrates feel pain **URL:** \ **Category:** Great Debates\ **Created:** [May 22, 2006, 7:30am UTC](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723 "2006-05-22T07:30:00Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![bup](https://avatars.discourse-cdn.com/v4/letter/b/6bbea6/32.png) [@bup](https://boards.straightdope.com/u/bup)\ **Post date:** [May 22, 2006, 5:24pm UTC](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723/21 "2006-05-22T17:24:55Z")
> [@CookingWithGas](#): > > The thing about science is there is no default position that must be proven or disproven. There are hypotheses that must be tested. It sounds like you are putting forward pain in all creatures as dogma. Nope. “Onus is on people who claim no pain” is a helluva lot different than dogma. I’m not a big dogma guy. I’ve stated a couple of times in this thread that I don’t claim to know. I’m OK with everyone being agnostic. What I’m railing against is the default conclusion that they _don’t_ feel pain. And, if I had to guess, based on the reasoning I’ve laid out, I would _guess_ that they do feel pain. But that’s a _guess_. > [@](#): > > This is a good point, but different from the scientific question. This last question takes us to GD territory. Let’s face it. If there were a front-page story on the Official World Scientific Authority Journal on Crustacean Biology that said “No Question–Lobsters Feel Excrutiating Pain When Boiled,” lemme tell you, it wouldn’t make a dent in the Maine lobster industry. I didn’t bring it up to argue on its own; I don’t care to argue what’s humane, in fact. I brought up what I would consider to be humane behavior as evidence that they’re not being entirely detached and coldly scientific - they came into it with a point-of-view and desired conclusion just as PETA does. The financial backing of those studies also has an agenda. IOW, if their interest was purely academic, they wouldn’t come out of the study with the conclusion it’s OK to boil them alive. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [May 22, 2006, 5:26pm UTC](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723/22 "2006-05-22T17:26:18Z")
It is indeed important to note that the ‘animals don’t feel pain’ thing has, in the past, been applied to all non-human lifeforms, even including vertebrates; even including mammals; even including _primates_. Of course this assertion was not so much based on any kind of science as it was based on religious anthropocentric dogma; animals didn’t feel pain because they were just meaty machines put here for our pleasure, service and consumption. The view that [some, possibly most or all] invertebrates do not feel pain is a bit different, because it’s based on studies of neurology, but even so, there are abundant uncertainties regarding the processes and systems the compose our own sentience, and nature has a funny habit of surprising us with exceptions whenever we state absolutely that ‘X can never ever do Y’. We may be right when we say that invertebrates are physiological and neurologically incapable of experiencing anything, including pain, but we just need to be careful, because having not quite worked out what sentience actually _is_, we might just be saying that “we’ll just know it when we see it”, which isn’t a particularly rigorous criterion. ---
**Author:** ![Inigo\_Montoya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inigo_montoya/32/124_2.png) [@Inigo\_Montoya](https://boards.straightdope.com/u/Inigo_Montoya)\ **Post date:** [May 22, 2006, 5:27pm UTC](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723/23 "2006-05-22T17:27:36Z")
Actually, it has been proven that only _tasty_ things don’t feel pain. Cockroaches, spiders, brussels sprouts and ovaltine exist in a perpetual state of agony. Which is only just and good. ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [May 22, 2006, 5:31pm UTC](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723/24 "2006-05-22T17:31:29Z")
> [@Lemur866](#): > > But the vast majority of invertebrates really do perform absolutely stereotyped behaviors that involve no processing by anything like a “brain”. Insects don’t walk the way we do. Each leg performs a “walking” behavior independently of each other and independent of the insect’s brain. There’s no central processing going on. This was my thought. As I understand things, many creatures have what might be called distributed processing. Their “brains” are broken up into various modules with each module performing a specific task. I really think the argument that they don’t “need” pain while more centrally organized vertebrates do is spurious. We might not need pain either, but that happens to be the way we are built. If we were built differently and merely react to heat by jerking away without feeling pain that would be OK too. In fact isn’t that the way it happens? Don’t we react to the heat and only feel the pain later? ---
**Author:** ![bup](https://avatars.discourse-cdn.com/v4/letter/b/6bbea6/32.png) [@bup](https://boards.straightdope.com/u/bup)\ **Post date:** [May 22, 2006, 5:31pm UTC](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723/25 "2006-05-22T17:31:51Z")
> [@Lemur866](#): > > We do have to be careful. Invertebrates are not a homogenous group. But in general, almost all invertebrates have very very simple nervous systems, and are absolutely incapable of learning. Lobsters and insects are higher than most invertebrates - they have a centralized nervous system. > [@](#): > > But the vast majority of invertebrates really do perform absolutely stereotyped behaviors that involve no processing by anything like a “brain”. Insects don’t walk the way we do. Each leg performs a “walking” behavior independently of each other and independent of the insect’s brain. There’s no central processing going on. What that demonstrates is that insects have stereotyped behaviors, but not that they’re incapable of learning. There’s no rule that they can’t be a little column A, a little column B. > [@](#): > > So we have to avoid falling into two traps, one is the classic trap of anthropomorphizing animals…the other trap is the trap of assuming that animals are completely different from us and must not have any thoughts or emotions similar to ours. Agreed. > [@](#): > > Now, back to pain. We shouldn’t expect organisms that are incapable of learning to be able to feel pain. But this question doesn’t have to rely on theory, we can answer the question empirically. Humans and other vertebrates have special nerve cells for pain reception. We can see pain receptor cells, and nerves that carry pain signals in other vertebrates. So it is absolutely clear that animals with this equipment are capable of feeling pain. Other animals don’t have anything of the sort. Cut a leg off an ant and it doesn’t even seem to realize it is missing a leg. So it is clear that some animals feel pain, others don’t, but we don’t have to make broad sweeping declarations, we can figure out which is which on a case by case basis. Agreed, mostly. The “case by case” basis thing is often hard though - right around the lobster level of sophistication. ---
**Author:** ![bup](https://avatars.discourse-cdn.com/v4/letter/b/6bbea6/32.png) [@bup](https://boards.straightdope.com/u/bup)\ **Post date:** [May 22, 2006, 5:38pm UTC](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723/26 "2006-05-22T17:38:36Z")
Just to make sure NOBODY POSTS MORE THAN ME IN THIS THREAD: 😉 > [@David Simmons](#): > > I really think the argument that they don’t “need” pain while more centrally organized vertebrates do is spurious. We might not need pain either, but that happens to be the way we are built. If we were built differently and merely react to heat by jerking away without feeling pain that would be OK too. In fact isn’t that the way it happens? Don’t we react to the heat and only feel the pain later? My answer to that again comes from the Aristotelan approach - since direct evidence is hard to come by, our best bet is to reason it out. If there were no need for pain, evolution would probably get rid of it, because pain makes for misery, and misery is less conducive to reproduction. That makes me think pain does have a purpose. Then we’re back to my earlier answer, which is that it accelerates learning, and my best hunch is animals that can learn experience pain. ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [May 22, 2006, 5:45pm UTC](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723/27 "2006-05-22T17:45:55Z")
If we define pain as “response to a noxious stimulus” then nearly everything with a nervous system feels pain. Perhaps we should ask the question as to whether lobsters _suffer_. ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [May 22, 2006, 5:49pm UTC](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723/28 "2006-05-22T17:49:19Z")
> [@Gary T](#): > > And the insistence that maybe they do feel pain suggests an inability to comprehend that they are not like us, with our minds and feelings. Inability? Naw. I know they’re not like us. I’m just not, however, going to define pain as unique to us or to our immediate family. I’m not going to assume that a pain-mimicking reaction must be “only” a response to stimulus just because you, or others, haven’t found a mechanism yet. There was a time when scientists hadn’t found the germ mechanism of disease, but it turns out it was there. The truth is scientists do not understand whether the stimulus/response mechanism is “unpleasant” or not – yet they insist that it isn’t. Insistence on something one has no evidence for is emotional. > [@Gary T](#): > > “Looks like” is pretty poor indicator. Those reactions may be indistinguishable to casual, uneducated observation, but they aren’t to thorough neurological investigation. “Looks like” is the only indicator we have. See Albert Einstein, et. al. Are you maintaining that “thorough neurological investigation” has discovered all possible knowledge? That nothing new might be learned? When “uber future investigation” comes along, “thorough neurological investigation” is going to look like [phrenology](http://en.wikipedia.org/wiki/Phrenology). “Thorough neurological investigation” is one way of looking, and subject to biases like any other human endeavor. > [@Gary T](#): > > “Seems” is an even poorer indicator than “looks like.” Yeah, it’s poor. But observation has served us well, and to reiterate what Einstein said, it’s our only way of interacting with the world. You may be misapprehending my intent. I’m not saying that a layman’s “seems like” is superior to research. I AM saying that plenty off biased, self-serving, fradulent, and human-aggrandizing research has been shown wrong in the past. The Earth is not the center of the universe; humans are not the only animals that talk, use tools, etc.; women are smart; minorities aren’t happier being slaves. Science has always been subject to fashion and fantasy and outright abuse, and surely you’re not arguing that it was so right up to the moment that your studies were published – but is from that point on incorruptible and accurate? Everything that we are came from somewhere on back down the line. The trend in science since Copernicus, at least, has been to discover that what we thought was unique to us is usually not. Neurological researchers inferred prions without having found any physical particles by watching what _seemed_ to be happening. They haven’t found the structures we currently associate with pain – ok, good point, but that doesn’t rule out them finding a new thing, or that they were wrong. Meanwhile, the strong assertion that pain CANNOT be happening certainly serves a human need among scientists, despite the inconclusive evidence. And that assertion is often accompanied by thinly veiled suggestions that those who do not accept it at face value are soft-headed, unscientific, stupid. I’m not a neurologist, but I know that I feel pain. Outside the closed universe that is my own bodily sensation and perception, I can only speculate…in a sense, that’s all any of us can do. > [@Gary T](#): > > I think you’re overlooking a huge body of research and evidence here. I might have characterized it as “mistrusting” a huge body of research and “mixed evidence and assertion”. Sailboat ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [May 22, 2006, 8:43pm UTC](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723/29 "2006-05-22T20:43:02Z")
> [@David Simmons](#): > > This was my thought. As I understand things, many creatures have what might be called distributed processing. Their “brains” are broken up into various modules with each module performing a specific task. Certainly it’s easier to have many more and better interconnections when you keep most of your nervous system in one place, but I don’t see why a distributed nervous system would necessarily present an absolute barrier to the formation of some kind of state of sentience. I’m not saying any such thing necessarily exists on this planet (although hive/colony-sentience, if it exists, would be a similar thing), but I think a sentient distributed nervous system is at least conceptually possible. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [May 22, 2006, 8:54pm UTC](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723/30 "2006-05-22T20:54:53Z")
> [@Lemur866](#): > > Insects don’t walk the way we do. Each leg performs a “walking” behavior independently of each other and independent of the insect’s brain. There’s no central processing going on. Nitpick really, but this isn’t actually completely true; if it were, the act of walking would be an uncoordinated mess and the insect would be prone to tripping over itself; ther _is_ coordination though; for example, many insects walk with an [alternating triangle gait](http://www.life.uiuc.edu/delcomyn/RSInsectWalking.html). None of this means there’s necessarily any central processing going on, but there certainly is networking. As I said above, I don’t see why central nervous systems need be an absolute requirement for awareness; what’s the big difference between a neural net that is packed into a skull and another one that is distributed throughout the body? ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [May 22, 2006, 11:29pm UTC](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723/31 "2006-05-22T23:29:32Z")
Sigh, I knew this was going to turn into a debate by the animal huggers. A shame really, it was a perfectly good factual question. Oh well Wesley, if you want to try asking again in a thread that hasn’t been hijacked I will be happy to answer your questions. I’m outta here. ---
**Author:** ![Speaker\_for\_the\_Dead](https://avatars.discourse-cdn.com/v4/letter/s/c77e96/32.png) [@Speaker\_for\_the\_Dead](https://boards.straightdope.com/u/Speaker_for_the_Dead)\ **Post date:** [May 23, 2006, 12:22am UTC](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723/32 "2006-05-23T00:22:27Z")
> [@Blake](#): > > Sigh, I knew this was going to turn into a debate by the animal huggers. > > A shame really, it was a perfectly good factual question. > > Oh well Wesley, if you want to try asking again in a thread that hasn’t been hijacked I will be happy to answer your questions. > > I’m outta here. No wonder it’s taking longer than we thought! Although I’m nowhere near qualified to join this debate, I’d like to put out a general call for cites, from both pro-pain and no-pain supporters. A few people have provided links, but while all were interesting, only a couple have been directly on-topic. Both sides have brought up studies that support their cases, but only a bit has appeared to be perused. I’m not doubting anyone; I just think it would make good reading and a more stable debate. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [May 23, 2006, 2:12am UTC](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723/33 "2006-05-23T02:12:02Z")
I don’t feel like quoting myself, so here’s a [link](http://boards.straightdope.com/sdmb/showthread.php?t=340786) to a related discussion. ---
**Author:** ![bup](https://avatars.discourse-cdn.com/v4/letter/b/6bbea6/32.png) [@bup](https://boards.straightdope.com/u/bup)\ **Post date:** [May 23, 2006, 5:40pm UTC](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723/34 "2006-05-23T17:40:40Z")
> [@Blake](#): > > Sigh, I knew this was going to turn into a debate by the animal huggers. > > A shame really, it was a perfectly good factual question. > > Oh well Wesley, if you want to try asking again in a thread that hasn’t been hijacked I will be happy to answer your questions. > > I’m outta here. Yeah, that’s pretty fair. You got shot down on a lot of your assertions, so I’m an animal hugger. :rolleyes: > [@SftD](#): > > Although I’m nowhere near qualified to join this debate, I’d like to put out a general call for cites, from both pro-pain and no-pain supporters. A few people have provided links, but while all were interesting, only a couple have been directly on-topic. Both sides have brought up studies that support their cases, but only a bit has appeared to be perused. I’m not doubting anyone; I just think it would make good reading and a more stable debate. Because the simple fact is, nobody really knows if invertebrates feel pain, and if some do, which ones. It’s the best factual answer to the question at present. ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [May 23, 2006, 6:14pm UTC](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723/35 "2006-05-23T18:14:20Z")
Animal hugger? Is name-calling outside the Pit one of those abilities that you have evolved, while still denied to us lesser beings? So I can’t discuss possibilities – anything I type has to be entrenched advocacy? Or at least stuffed with straw and dismissed as such. And whatever you say is unproved theory, but whatever I say is unfounded belief? At least the argument I advanced meets the scientific principle of parsimony; it doesn’t require the invention of a new explanation for why an animal recoils in apparent pain, nor a completely different brand-new hypothesis of how pain suddenly appeared in humans, out of nothing. All my argument requires is that humans be able to mislead themselves and/or others, and that it is theoretically possible we have not discovered everything yet. Both have pretty firmly been established in other cases. That’s parsimony, baby. Perhaps your side is right. Perhaps mankind – maybe even white male Europeans, if we’re lucky – is the shining center of the universe; possessed of sensations denied to all lesser beings, that sprang complete into his godlike consciousness, morally perfect, beyond any need for empathy, the just arbiter of life and death, knowing everything about all biological structures in only a few decades of indifferent study, able to definitively state what others experience, without qualm or backward glance, and infallibly immune to correction from hypothetical subsequent discovery. But I’m betting against it. Sailboat ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [May 23, 2006, 6:28pm UTC](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723/36 "2006-05-23T18:28:43Z")
> [@Mangetout](#): > > It is indeed important to note that the ‘animals don’t feel pain’ thing has, in the past, been applied to all non-human lifeforms, even including vertebrates; even including mammals; even including _primates_… Hell, up until 20 years ago, it was common knowledge that baby humans didn’t feel pain and boys needed no pain medication during or after circumcision. There’s still a huge resistance to giving babies pain medication - I had to threaten to take my baby home AMA after retinopathy surgery because they wouldn’t give her so much as infant Tylenol…but I digress… I don’t understand where this “need” thing is in evolution. Evolution doesn’t respond to “need.” We don’t “need” tonsils, or an appendix or a second kidney or sperm that mal-develop at body temperature. But we have them anyway. I’m not saying invertebrates feel pain, I’m just saying “they don’t need to” is a silly reason to think they don’t. I’m far more accepting of the “they don’t have the neurological wiring to feel pain” response. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [May 23, 2006, 11:08pm UTC](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723/37 "2006-05-23T23:08:10Z")
> [@WhyNot](#): > > I’m far more accepting of the “they don’t have the neurological wiring to feel pain” response. Sure, and that argument may well be right, but there are a couple of things we must beware of: -firstly, that we aren’t just saying “well, it’s not built the way we are, so it cannot have equivalent functions” - on its own, fallacious, because there are often multiple possible solutions ot a problem (and we know that evolution is reasonably good at finding them) -Secondly, that we aren’t just expressing a rather subtle tautology; yes, our kind of nervous system is the only kind we know that can support sentience, but the really important point is _it’s the only one about which we **can** know that_; that we cannot know for sure that another being is sentient is a philosophical problem that’s been with us for ever; we must not say that because we can’t know whether it is or not, then it definitely isn’t. ---
**Author:** ![samclem](https://avatars.discourse-cdn.com/v4/letter/s/a9a28c/32.png) [@samclem](https://boards.straightdope.com/u/samclem)\ **Post date:** [May 23, 2006, 11:17pm UTC](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723/38 "2006-05-23T23:17:25Z")
Since this one has become a Great Debate, let’s move it there. **samclem** General Questions moderator ---
**Author:** ![Miller](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/miller/32/481_2.png) [@Miller](https://boards.straightdope.com/u/Miller)\ **Post date:** [May 23, 2006, 11:56pm UTC](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723/39 "2006-05-23T23:56:36Z")
Is the OP a question, or a proposal? “Why shouldn’t invertebrates feel pain? I mean, fuck those guys, all, ‘Look at me! I don’t have an internal skeletal structure!’ Let’s kick their ass!” ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [May 24, 2006, 12:41am UTC](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723/40 "2006-05-24T00:41:51Z")
> [@Mangetout](#): > > Nitpick really, but this isn’t actually completely true; if it were, the act of walking would be an uncoordinated mess and the insect would be prone to tripping over itself; ther _is_ coordination though; for example, many insects walk with an [alternating triangle gait](http://www.life.uiuc.edu/delcomyn/RSInsectWalking.html). None of this means there’s necessarily any central processing going on, but there certainly is networking. Not necessarily; IIRC robots designed to imitate that sort of distributed processing manage with zero central control. The gaits emerge spontaneously, and aren’t programmed into the machines. Of course that doesn’t prove insects do that, but it shows it’s possible. Note that your linked article makes many references to sensory input; that’s how such robots work. They react to the input of many sensors, not to any central control. It also points out how the legs are controlled by nerve clusters in the leg, not outside nerves. I’ve read that an eating wasp can have it’s abdomen cut off and it’ll just keep eating; that’s an example of how uncoordinated their nervous systems are. [Previous page](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723.md?page=1) [Next page](https://boards.straightdope.com/t/why-shouldnt-invertebrates-feel-pain/357723.md?page=3)