Animals and pain

Factual Questions
1

What is pain? And can animals feel it?

Growing up, I was taught that “scientists agree that animals can’t feel pain like humans, because our brains are unique”. Since then, I’ve heard an ever-growing list of animals which, it is now thought, can feel pain the same as (or at least analogous to) humans – dolphins, primates, other mammals, cephalopods, birds, …

It seems obvious to me that either “scientists” don’t really have a clue, or that the general people doesn’t really have a clue what science has to say about the matter.

Yet people still freely assert that ‘reptiles/insects/fish/etc. certainly cannot feel pain, because their nervous systems are underdeveloped’. This catches me as being unconvincing.

With the recent decision by Switzerland to ban the live boiling of lobsters, I am seeing the argument flare up again. And it seems that most (but certainly not all) “scientists” agree that lobsters are incapable of feeling pain, and that they are simply ‘reacting to stimuli’.
According to the University of Maine’s Lobster Institute, “[f]or an organism to perceive pain, it must have a complex nervous system. Neurophysiologists tell us that lobsters, like insects, do not process pain.”

I must ask: what the heck is the difference between ‘reacting to a stimulus’ and ‘experiencing pain’? It seems like scientists assume that a complex nervous system is a minimum requirement for pain, then use that assumption to assert that ‘therefore, insects/lobsters cannot feel pain’.

It seems to me that, essentially, the difference between pain and ‘reacting to stimuli’ is a presumption of consciousness. And as consciousness is illusory and indemonstrable (I know, getting philosophical here), the difference between pain and ‘reacting to stimuli’ is illusory and indemonstrable.

2

My sympathy/empathy for some creature is not based on the size of their brain or their understanding of what is happening to them. It is based on what I feel if I presume they are suffering. I don’t like it and I will go out of my way not to cause it.

3

Consider something like a little robot that consists only of a wheel and a light sensor. If you shine light on the sensor, the wheel turns and moves the robot away from the light. This robot doesn’t “feel” the light. It just reacts to it.

The nervous systems of many animals aren’t much more complicated than that. The common theory is that they don’t “feel” pain, their nervous systems are just hard-wired to react to it.

People don’t think of plants as feeling much of anything, especially considering that they don’t even have nervous systems. But plants react to light (they’ll grow towards it, or open and close their leaves and flowers in response to it), and plants like a Venus Fly Trap can even sense prey and capture it.

In a sense, many simple animals aren’t much more complicated than plants. Most insects just react to things. They don’t “feel” or experience pain. Give them some sort of painful stimulus and they’ll react to it. Set up the exact same situation though and they won’t know that the pain is coming and won’t anticipate it in any way. The lobster argument basically boils down to this. The lobsters don’t feel pain. Their nervous systems are just hard-wired to react to it, in a way similar to the automatic light avoiding robot above.

Much more complex animals feel and experience pain. Dogs, cats, chickens, horses, etc. all will remember pain and will avoid a situation where they know pain is coming. The thing is, part of the pain response is automatic, even in more complex animals, and even in humans. If you accidentally touch a hot stove, you don’t stop to think “gee, that hurts, I should probably move my hand”. You just move your hand instinctively. You just react. In fact, you’ve probably moved your hand completely away from the stove before your conscious mind finally catches up and thinks “oh shit, that hurt!”

Another thing is that there is no clear dividing line between lobsters and humans. It’s more of a gradual scale, with animals getting more and more complex along the scale.

Consciousness is, as you note, a bit ill-defined at the moment. If you try to determine consciousness as your dividing line between animals that feel pain and animals that don’t, it still gets difficult to define. Humans aren’t the only creatures with language, for example. Whales and dolphins use language to communicate to each other. Monkeys can teach other monkeys to avoid things. Dogs have a fairly simple language (bark, growl, whimper, wag…) but they can teach other dogs certain things. So where is the line? Animals tend to have a spectrum of complexity with their nervous systems. It’s all just different shades of gray.

Anyway, that’s the issue. You can think of lobsters as basically being the biological equivalent of that light-avoiding robot. That’s the argument, at least. What you do with that philosophically is up to you, but that’s a topic that is better suited for a forum other than GQ. Try GD or IMHO if you want to delve into that further.

4

I’ll point out that that idea contains so many fallacies that anyone saying it would be laughed out of junior debating.

Indeed one could take it far enough to claim that no-one other than you can feel pain as your brain is unique to you. Solipsism comes soon after when you try this line of argument.

5

This is a straw man. I’d like to see a cite that any scientist has ever claimed that other mammals don’t feel pain. Scientists don’t think that, and never have; “general people” don’t think that, and never have.

6

I’m not sure you comprehended what I said (my fault or yours, I’m not sure). I never claimed that scientists have claimed that mammals don’t feel pain, only that that’s what I grew up hearing – note, this was coming from a strongly religious family who argue that the Bible says that humans are special and animals are essentially our slaves and play things.

7

That’s essentially my point. We cannot even show that another human is capable of feeling pain; that’s just an assumption. So I wonder how it is that scientists can make any sort of confident pronouncement regarding animals’ abilities to feel pain.

I’m unaware of any convincing reason to declare that “<insert animal, such as dolphins> experience pain, whereas <insert animal, such as lobsters or fish> do not”. It seems to me that both animals, when sensing something dangerous/damaging, will instinctively try to escape that stimulus.

8

If the argument puts humans in a ‘special’ category that excludes all other animals all the way up to other primates, then it’s essentially a religious assertion of some kind (even though it may not present as such).

Even if it is accepted that humans evolved, but that humans are literally the only organisms on the planet capable of experiencing pain, that would have to mean that appreciation of pain was pretty much the last thing we acquired as we evolved - it then becomes hard to explain why we were motivated to avoid harm before that point.

There are animals that don’t seem to exhibit any response to injury or risk of damage - jellyfish just carry on doing their thing even while something is taking bites out of them - ants are pretty much disposable units in a colony and will ignore damage or run into danger if there exists a stimulus to do so.

9

Did you not understand my robot example? Does the robot feel pain when exposed to light? Most people would say no. And yet the robot moves to escape that stimulus, which is exactly your argument.

10

I understood your example. I didn’t reply, because I had replied to 2 others already and didn’t want to monopolize the forum.

Your example fits nicely into the kinds of things I’m talking about. How sensors, pain and consciousness relate to one another.
The thing that stuck out to me was when you said “You can think of lobsters as basically being the biological equivalent of that light-avoiding robot”. This seems like nothing more than an assumption to me. It is assumed that lobsters’ biological stimulus-avoiding functions are too basic to be called ‘pain’ … but without having any way to delineate how the ability to feel pain is any different to the ability to sense and avoid it. It seems obvious to suggest that the light-avoiding robot cannot feel pain … but is that not just an anthropocentric view of pain?

By what metric can we assert that a dog can feel pain, but a snake cannot? Or if a snake can feel pain, then by what metric can we assert that a snake can feel pain, but a lobster cannot? Where’s the yardstick?
The only attempt at a yardstick that I’ve been privy to is the amazingly vague answers such as “their nervous system isn’t as advanced”.

11

I would say that your robot is certainly experiencing light, and is reacting to it in the same way as it would to pain. I’m not sure I would say that it actually is pain, but that’s only because a bright light isn’t something that is likely to cause harm to the robot. Rebuild your robot to avoid things that cause it harm, and yes, I would say that it’s feeling pain. Why wouldn’t one say that?

12

I think any organism with pain sensors “feels” pain; the question is how to assess the quality or depth of that “feeling.” That’s a very difficult question, but if you decide that “number of neurons” is a very very VERY crude proxy for the “quality and depth of a brain’s feelings,” then the following (Very crude) sorted table, abridged from Wikipedia’s, might have interest:
Roundworm 302
Jellyfish 5,600
Medicinal leech 10,000
Sea slug 18,000
Lobster 100,000
Fruit fly 250,000
Ant 250,000
Honey bee 960,000
Cockroach 1,000,000
Zebrafish 10,000,000
Frog 16,000,000
Smoky shrew 36,000,000
House mouse 71,000,000
Nile crocodile 80,500,000
Zebra finch 131,000,000
Brown rat 200,000,000
Red junglefowl 221,000,000
Guinea pig 240,000,000
Pigeon 310,000,000
Ferret 404,000,000
Common starling 483,000,000
European rabbit 494,200,000
Octopus 500,000,000
Common marmoset 636,000,000
Barn owl 690,000,000
Cat 760,000,000
Magpie 897,000,000
Eurasian jay 1,085,000,000
Emu 1,335,000,000
Raccoon 2,148,000,000
Raven 2,171,000,000
Domestic pig 2,220,000,000
Dog 2,253,000,000
Blue-and-yellow macaw 3,136,000,000
Striped hyena 3,885,000,000
Lion 4,667,000,000
Rhesus macaque 6,376,000,000
Brown bear 9,586,000,000
Giraffe 10,750,000,000
Yellow baboon 10,950,000,000
Orangutan 32,600,000,000
Gorilla 33,400,000,000
Human 86,000,000,000
African elephant 257,000,000,000

(I’ve bolded a few cases, e.g. birds with lowest and highest counts. No cetaceans appear in the relevant Wiki list, but some have more neurons than humans.)

13

That was partly why I said that the base statement contains so many fallacies. “scientists agree” is already a huge problem before you go anywhere else. As they say in the classics [cite?]. It is also an appeal to authority argument, usually made by those trying to justify their actions (along with fish feel no pain because they are cold blooded.)

Rather criticise these agreeing scientists, the problem is first to actually find these scientists and discover what it is they agree on. The usual answer is that they are pure imagination. An invention of the mind of someone trying to represent an argument as having some foundation. Alternatively you may discover that the quoted science is quoting someone like Aristotle, and neglecting a few thousand years progress.

In reality no modern scientist would be so presumptuous to draw a line about the reception of pain. However for those animals where we have a pretty clear idea of the limits of their brain function - where we really do see that there are no more neurons than needed to implement little more than the light avoiding robot, we might feel safe. But you are not going to find any scientist who is going to divide humans from the other animals. That is, as noted earlier, religion, not science. You would probably be hard pressed to find any scientist who thinks there any vertebrates that don’t feel pain,

14

Just because a lifeform can avoid noxious stimuli doesn’t mean it consciously feels pain. The neurology necessary to be capable of pain and to plan around it is pretty advanced, and most lifeforms don’t have it.

My understanding is that only vertebrates can feel physical pain, and only mammals can feel emotional pain.

Advanced social animals like humans, dolphins, elephants, etc probably also have psychic pain, the ability to feel guilt about the past or fear of the future. I’m guessing a lot of mammals lack that ability to worry about the future or get stuck in the past. I’d assume only social animals can feel shame, but I am just guessing.

Basically the more advanced your brains get, the more kinds of pain you are capable of.

15

Certainly most animals can’t plan around pain, but is the ability to plan really part of “pain”? I’d argue that the ability to plan to avoid pain is basically the same ability as the ability to plan to gain pleasure, and independent from both pain and pleasure.

16

As someone who has lived a couple decades with parrots, I have to disagree with some of that. Highly social birds, like parrots, do seem to feel emotional pain. I don’t know if they feel guilt about the past but they certainly do remember the past, and I think they have some ability to anticipate the future although not nearly to the extent humans do.

17

I see what you did there. :stuck_out_tongue:

18

It’s interesting, because the argument quickly veers off into spirituality and unknowable philosophy stuff - the robot isn’t feeling pain because it has no inner monologue or thought-life - except that we can’t be sure of that with other people than ourselves anyway.

I do wonder if actually people are talking about ‘fear of pain’ rather than ‘feeling pain’ - but even then, the programming of a robot to avoid certain undesirable stimuli could be described as ‘fear of pain’.

19

The robot analogy doesn’t work when discussing the subjective feelings of living things. You could argue that humans are also just having a nervous system response to a stimulus when we wail and groan in agony from something very painful. And nobody would argue that person wasn’t feeling pain just because they’re hard wired to respond to it that way.

The question isn’t and has never really been if other animals ‘feel’ pain. Of course they do. The argument some have put forth is that not having the higher reasoning capacity that humans have it just isn’t as big of a deal to them as it is for us. We are able to think: “I’m in pain. This is bad. This means an injury or illness. Oh the pain. Oh woe is me. ouch ouch ouch” etc. Simple life forms don’t seem to have the capacity to experience that kind of emotional response to pain.

Occam’s razor and all, the simplest assumption is that any animal with a brain almost certainly does experience some level of emotional suffering along with the feeling of pain.

20

That could be. There is a connection between social animals and better brains because social animals need bigger brains to navigate the complexities of social life. The smartest animals tend to be social.

My understanding is most of our emotions come from the limbic system, but I don’t know what kind of emotional life social non-mammals have.

According to this, birds have a limbic system. But I thought that was only in mammals. I’m not sure how that works.