Welcome to Entanglements. In this episode, hosts Brooke Borel and Anna Rothschild ask: Which animals are conscious? Are octopuses conscious? What about lobsters? Or mosquitoes? How we answer this question directly influences animal welfare, among other things. But actually measuring consciousness isn’t so simple, and researchers aren’t in agreement over which animals have it, and which do not.
Their guests this week are Heather Browning, a philosopher at the University of Southampton in the U.K, and Deb Brown, a philosopher and the director of the Critical Thinking Project at the University of Queensland in Australia.
Below is the full transcript of the podcast, lightly edited for clarity. You can also subscribe to Entanglements on Apple Podcasts and Spotify.
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Archival Clip – Voice 1: Across the Atlantic the nervous systems of lobsters and other invertebrates are at the center of a bill that is making its way through Parliament.
Anna Rothschild: Have you heard of this, Brooke?
Brooke Borel: Is this about boiling lobsters alive?
Anna Rothschild: Partly, yes.
Brooke Borel: I mean, I’ve heard you shouldn’t do that. But I missed the part where lawmakers got involved.
Anna Rothschild: Yes, well, a few years ago, the U.K. passed a law formally recognizing lobsters — and crabs and some other sea creatures — as sentient beings.
Archival Clip – Voice 2: It believes the science is in: Lobsters are sentient animals. In other words, what’s practically a bug on the bottom of the ocean has feelings.
Anna Rothschild: And in response, lawmakers in England are taking steps to ban certain practices that they now consider animal cruelty, like boiling lobsters alive.
Brooke Borel: So lobsters will have legal rights?
Anna Rothschild: British ones might soon. But not everyone thinks this is the right move — or that lobsters and other crustaceans, or a bunch of other animals for that matter, truly have feelings.
Brooke Borel: Welcome to Entanglements, the show where we dig into the thorniest scientific debates — and try to find common ground. I’m Brooke Borel, articles editor at Undark magazine.
Anna Rothschild: And I’m science journalist Anna Rothschild. And today we are getting into animal consciousness — or more specifically, the type of consciousness that researchers have been looking at: animal sentience.
Brooke Borel: Oh, good, a nice light episode today.
Anna Rothschild: Right. So this is something philosophers and scientists have been thinking about for, I don’t know, probably forever — you know, can other animals feel feelings? Do they have a conscious experience of the world the way we do?
Brooke Borel: Right, and what does that say about how we should be treating them?
Anna Rothschild: That’s the big question. And we’re finally at a point where researchers can actually approach this question scientifically. So today my guests are two philosophers who have very different ideas about what the right scientific approach is, and where to draw the line that separates conscious beings from non-conscious ones.
[MUSIC]
Anna Rothschild: Do you think octopuses are conscious?
Heather Browning: I definitely think octopuses are conscious.
Anna Rothschild: This is Heather Browning. She’s a philosopher at the University of Southampton in the U.K. She studies animal minds and the ethical implications of how we treat other creatures. And Heather’s been thinking about all this for a long time — since before she even became a researcher.
Heather Browning: So I started out actually as a zookeeper. And I guess I became interested then in the question of what was happening inside the animal’s minds because you spend a lot of time trying to make sure that the animals are happy and that they have good lives. And so I became increasingly interested in: How do we figure out whether these animals are feeling anything at all, and if they are, what they’re feeling?
Anna Rothschild: In her view, this all centers on the question of whether or not those creatures are conscious.
Heather Browning: The reason that we care so much about whether animals are conscious is because essentially when we’re thinking about, “Should we care about the good of this creature? Should it play a part in our ethical deliberations about what’s right or wrong?” all of those things tend to be based around whether or not that animal is conscious. We don’t usually think that we have any strong moral duties towards, say, rocks or rivers, or perhaps even trees. You know, we pull a leaf off a tree, it doesn’t seem like you’ve done something morally wrong, but we do feel like we have moral duties towards conscious creatures because they are able to experience these pleasures and sufferings that we think matter.
Brooke Borel: OK, and what exactly does Heather mean when she calls a creature “conscious”?
Anna Rothschild: Yeah, unsurprisingly that’s kind of hard to define, but here’s how she thinks about it.
Heather Browning: So the difference between sort of being conscious and not being conscious is having that first person point of view, that there’s some sort of “I” looking out at the world who is able to feel an experience. And so it’s the difference between, you know, I can feel what it’s like when rain falls on my arm, but a rock or a chair doesn’t feel anything when water falls on it.
Brooke Borel: So, a non-conscious creature wouldn’t exactly be like a rock or a chair, right, because it still reacts to the world around it. But maybe it would be sort of like a computer — basically hardwired so that a certain input causes a certain output? But it’s not actually feeling anything?
Anna Rothschild: Right. So, think about a jellyfish. A jellyfish doesn’t even have a brain to process experiences — it just has a bunch of nerves linked together. So if you brush against it and it stings you, it’s not thinking, like, “Hey, this person is a threat and I have to protect myself” — that’s just an automatic response that happens when it gets touched.
Brooke Borel: Like a reflex.
Anna Rothschild: Exactly. But Heather thinks lots of animals probably are conscious — more than you might assume. I want to add a quick caveat here, which is that, up until now, we’ve been talking broadly about consciousness. But what most scientists, including Heather, specifically study is a basic type of consciousness called sentience.
Brooke Borel: OK, so what’s the difference there?
Anna Rothschild: Yeah, so sentience is basically just a capacity for feeling. So a sentient creature doesn’t necessarily have to be deeply self-aware or have some rich experience of the world the way we do. It just has to be able to feel “Am I sensing pleasure or am I sensing pain?” But for the purposes of this conversation, you’ll hear us use the terms interchangeably.
Anna Rothschild: So, just to get a baseline idea from you, which groups of animals do you think are conscious?
Heather Browning: Yeah, so I think — I have a very high amount of confidence that all vertebrate animals are conscious. So that’s the mammals like ourselves, it’s the birds, it’s reptiles and amphibians, and it’s the bony fishes as well. And then I’m also fairly confident that at least some groups of invertebrates are conscious as well. So that includes the cephalopod mollusks, which are the octopuses and squids, decapod crustaceans — that’s our crabs and lobsters — and also probably insects as well, or at least a large number of insects. And beyond that, I guess I’m waiting for more evidence on some of the groups beyond those.
Brooke Borel: Even insects. OK, does this mean I should feel bad about killing mosquitoes now?
Anna Rothschild: Maybe. At least if you think consciousness is as widespread as Heather does.
Brooke Borel: I don’t know, I still plead self defense on that one.
Anna Rothschild: Fair enough.
Brooke Borel: Anyway what makes Heather so confident that all these animals are conscious?
Anna Rothschild: Well, a few years ago, the British government was working on updating animal welfare legislation, and they wanted to make sure the laws protected any animals that were sentient. So, Heather and her colleagues were asked to publish a report on sentience in cephalopods, so octopuses and squids, and certain crustaceans, like crabs and lobsters.
Heather Browning: And so we essentially went out and we reviewed as much research as we could find, which was several hundred research papers about these different groups of animals, and in doing so essentially did find that there was strong evidence in our minds that they passed all the criteria that we had set for being conscious.
Brooke Borel: So what are those criteria? I mean, how do we actually figure out if an animal is conscious or not?
Anna Rothschild: That is the question. I mean, one of the biggest problems with studying consciousness at all is that by definition we can’t know what another creature’s individual experience of the world is.
Brooke Borel: Right. And I guess we can’t just look for consciousness in the brain.
Anna Rothschild: Not exactly. I mean, researchers definitely look at the complexity of the brain as a clue, but we can’t just scan the brain and tell whether or not the lights are on.
Heather Browning: At the moment, given that our understanding of the neurobiology of consciousness is still quite basic, given that our theories of consciousness, of what it is, of why it evolved, they’re all still developing — this is a new science, it’s a new research area, and so we don’t have strong answers. So what we do instead is we look for a range of different markers that seem to be suggestive of sentience from different pathways that come from different types of evidence.
Anna Rothschild: In Heather’s work, one important line of evidence is pain. Pain has been really well studied in lots of species already, so lots of consciousness researchers focus on signs that animals experience pain.
Heather Browning: When we did these reports, we were looking for particularly, endogenous analgesics, which are essentially the internal painkillers that animals have that we know that in ourselves work to modulate the experience of pain and activate to make painful stimuli less painful. So if something like that is existing. If they also show responses to externally administered analgesics or anesthetics, another line of evidence there.
Brooke Borel: And that’s because if animals have natural painkillers — or if they react to external painkillers — that would imply they’re having some kind of conscious experience?
Anna Rothschild: That’s the idea. And so researchers like Heather look for responses to pain or painkillers in animals’ behavior. They’re especially interested in complex responses to pain — so not just an animal that runs away from an electric shock, but one that changes its behavior in more sophisticated ways.
Heather Browning: One of the studies we reviewed in crabs, for instance, was looking at motivational trade-offs in hermit crabs. Hermit crabs don’t grow their own shells; they use the discarded shells of other animals. And so they have different shells that to them are more or less preferred. And what this experiment looked at was essentially how these animals would make decisions about when to vacate their shell when they were given a small electric shock inside that shell — so they were experiencing some pain and how they would make the decision of how much pain they would endure before they left that shell. And they found that they would stay much longer in the preferred shell than the non-preferred shell, which should show that they were sort of representing the value of that shell as well as the electric shock, making that decision.
Anna Rothschild: And this line of evidence related to pain is especially important to researchers like Heather because of its ethical implications.
Heather Browning: So if a creature is sentient but it couldn’t experience pain for some reason, say it only had sort of fear and hunger and other kinds of states, perhaps that’s not quite as bad and we wouldn’t have to worry so much about the kinds of things that we’re doing to it. So we thought pain experience is one of the most prevalent causes of suffering, and so the capacity for pain seemed like a thing that was worth focusing on for that reason too.
Brooke Borel: So what did they ultimately find?
Anna Rothschild: Basically they concluded that all the animals they were studying were likely to be sentient. So, that includes octopuses and squids, and, kind of to their surprise, also crabs and lobsters.
Brooke Borel: Wow.
Anna Rothschild: Do you think people should change their behavior towards these animals based on what you found?
Heather Browning: Yeah, I definitely think that there are some changes in behavior that need to sort of follow from this. So one of the things I think that our findings on octopuses suggests is that they are not a good candidate for industrial farming. So there have been some proposed octopus farms in a couple of parts of the world where there would be sort of large-scale, intense farming. And I think given the sentience of octopuses, that octopus farms shouldn’t, shouldn’t get off the ground.
Brooke Borel: Does Heather feel that way about all farming?
Anna Rothschild: She only specifically mentioned octopuses in our conversation. That said, in their report, she and her colleagues did explain a little more. They say that they don’t think octopuses can be farmed humanely — not just because they believe they’re sentient — but also because they’re solitary and aggressive animals that wouldn’t do well cooped up on a farm.
Heather Browning: And I think the other really big thing that comes out of this is thinking about how we do humane slaughter of these animals. Particularly when we think about crustaceans — the live boiling of lobsters is a huge problem here.
Anna Rothschild: Were you happy with how your report was used to influence policy change in the U.K.?
Heather Browning: Yeah, we were really happy with that. The government had commissioned the report to inform their views as they were developing this legislation, but they were under no obligation to include our findings. So it was really, really wonderful to us to find out that they had decided to give these animals protection under the law, and then to see the widespread public response as well. It was so overwhelmingly positive. We were worried that people would think that this was crazy, that we were suddenly extending concern and protections to crabs and lobsters and octopuses. But yeah, overwhelmingly people really seem to take this on board and think that this was something that was justified and that they’re happy to see continue.
Brooke Borel: Alright, but I take it that your next guest does not fall into this camp.
Anna Rothschild: Let’s just say she’s a little more skeptical.
[MUSIC]
Anna Rothschild: Do you think octopuses are conscious?
Deb Brown: Well, I don’t think they are capable of pain. I don’t see the evidence that there’s any consciousness needed to explain even their more complex behaviors.
Anna Rothschild: This is Deb Brown. She’s a philosopher and the director of the Critical Thinking Project at the University of Queensland in Australia. She collaborates closely with the neuroscientist Brian Key to study the neural basis of pain, and she helped found the university’s neurophilosophy lab to explore how the brain experiences feelings. And when it comes to her reasons for studying animal consciousness, she’s largely in agreement with Heather.
Deb Brown: I mean, how we understand the inner life of animals should really determine how we relate to those animals. Of course there’s the animal’s welfare and the question of whether we need to extend welfare protections to those animals that are capable of feeling pain or who have some form of consciousness.
Anna Rothschild: Like Heather, Deb is also interested in which animals have a conscious experience of pain.
Deb Brown: Pain is a form of suffering. We think suffering is bad. And if there are other creatures capable of suffering, we ought not to contribute to their suffering, right?
Anna Rothschild: But even though she and Heather essentially have the same goal, Deb has drawn some pretty different conclusions about what animals actually experience suffering.
Deb Brown: I guess from the work I’ve been doing with Professor Brian Key, who’s a neuroscientist I work with, we find it hard to attribute pain beyond creatures that have a cortex — that have cortical structures.
Anna Rothschild: The cortex being the part of the brain that handles a lot of our higher brain functions — including how we experience sensory information, like pain. It’s kind of traditionally been thought of as the seat of consciousness in the brain, although as with most things related to consciousness, that’s up for debate.
Deb Brown: I mean, all mammals, right down to rats and mice, have cortical structures, so there’s good reason for thinking that they have the right kind of neural architecture to support pain. But beyond that, once you get to sort of phylogenetically distant animals like, say, fish and amphibians and invertebrates, mollusks, insects, and so on, we just don’t find evidence of the sufficiently complex neural circuitry that’s required to sustain pain in us and other mammals.
Brooke Borel: Interesting. So, how does that square with the findings Heather described, where octopuses and crabs and so on seemed to be responding to pain?
Anna Rothschild: Yeah — so, this is where it’s important to understand the difference between pain and something called nociception. Nociception is just an organism’s ability to detect and avoid harmful stimuli, like a shock or a toxic substance. But you don’t necessarily have to be conscious to do that.
Deb Brown: I mean, every organism has nociceptors. Even plants have nociceptors. A plant will move away from a plant trying to encroach in its area. Or plants can even detect the vibrations of predators and could close their leaves up, right? And cells have nociceptors, right? You can kind of poke a cell and it will move away, but there’s no consciousness implied there.
Anna Rothschild: Right. It’s an involuntary reaction, but it doesn’t necessarily mean you’re having feelings about it.
Deb Brown: Yes, exactly. It’s a reflex. So it’s important to keep that distinction between nociception, which is non-conscious, and pain, which is a kind of higher-order awareness that the brain has of its nociceptive processing.
Brooke Borel: Gotcha. So she’s not saying that these octopuses and crabs aren’t responding to harmful stimuli in complex ways — she’s just not convinced that they’re doing so consciously.
Anna Rothschild: Exactly.
Brooke Borel: OK. So I get why that’s possible, biologically. But what makes Deb so sure that crabs and octopuses aren’t actually conscious?
Anna Rothschild: Yeah, so this goes back to their brain circuitry again. In humans, there’s some pretty clear evidence that our ability to feel pain is tied to the cortex.
Deb Brown: A lot of the work done understanding the relationship between pain and the cortex actually occurred after the First World War when a lot of soldiers were coming back with shrapnel injuries to their cortex. And doctors were able then to correlate those sorts of lesions with deficiencies in their feeling, right? So that if you had shrapnel damage to some part of your brain, you would have a corresponding deficit on the other side of your body in terms of your ability to feel pain. So in humans, we know without the cortex, we don’t feel pain. And so then the thought was that’s a necessary condition in us for pain, and so we should look for something that sort of performs the same function as that in other animals.
Anna Rothschild: And that’s the piece that Deb thinks is missing in animals like crabs and lobsters.
Brooke Borel: I see. So basically she’s saying you can’t prove that an animal consciously feels pain just by looking at behavior — you have to look at how its brain is wired.
Anna Rothschild: Right.
Brooke Borel: So, I take it she’s familiar with the report Heather worked on?
Anna Rothschild: Oh, yes.
Brooke Borel: How’d she feel about that?
Anna Rothschild: Well…
Deb Brown: It seems to be sort of stacked rather heavily in favor of behavioral studies. You know, the kind of group that got together to do that report consisted largely of psychologists and animal welfare people and philosophers and there was sort of a noticeable absence of neuroscientists. And I think that’s a mistake. I think there’s been so much work done on the neuroscience of pain and across different animal models that one has to really take into account that research.
So, essentially what Brian Key and I have done is to work through a lot of that research and to try and come up with a model for understanding how pain computationally works. So in our view, we see pain is essentially connected with this idea that when a brain gets to a certain level of complexity it needs a way of understanding why it’s behaving as it did. I mean, imagine being sort of aware of your behavior, but not aware of any of the inputs to your behavior. Right? So imagine you were just fleeing from some kind of event or you were just grabbing something and you were just behaving and you didn’t have any way of understanding why.
Anna Rothschild: Yeah.
Deb Brown: We think that the brain actually needs to assign cause to something and it needs to assign something to a cause within itself, if you like. But the trouble is in the brain you’ve got this vast network of activity happening all the time. And so, from a computational point of view, it would just be paralyzing for a brain to try and sort out what are the causes of its particular behaviors. And what sentience does is certainly sort points a spotlight and says, “Look here, this is what’s causing you to engage in that aversive behavior.” So it helps the brain to kind of locate the cause and then make predictions and modify its behavior on the basis of how it’s assigning cause.
Anna Rothschild: So in Deb’s view, pain is one of the things that plays this role. For example, after your hand jerks back from a hot stove, you feel pain even though your body has already taken care of protecting you. That’s your brain’s way of putting a spotlight on the thing that caused your reaction so you can potentially avoid it next time.
Deb Brown: So it requires a certain amount of neural complexity. It requires layers of neurons that are capable of reading lower level layers of neurons, which we don’t see in a lot of these phylogenetically distant animals. So that’s part of the problem. I mean, just to take the octopus brain, for example, right? The octopus brain has 40 million neurons. Which is, in the scheme of things, not that many neurons.
Anna Rothschild: Especially if you compare it with other parts of the octopus’s nervous system — 130 million nerve cells controlling its eyes and 350 million controlling its arms.
Deb Brown: So for the octopus from an evolutionary perspective, a well advanced visual system and arms that can do a lot of things at the same time in a coordinated fashion is much more important than the brain. Whereas for us, we really depend on a lot more brain processing. So at the moment, we’re actually sort of trying to unpack what the function of pain might be. And in particular, we don’t see pain as having a primary function in determining the nocifensive behavior that’s pretty much kind of governed and controlled rather well by reflexes. Pain has a sort of more executive function, in our view.
Brooke Borel: OK, so let me see if I got this straight. In your first conversation, with Heather, it seemed like the assumption was that pain drives behavior. So, it’s pain first, then the behavior: You feel something that hurts, then you move away from it. But then we have Deb arguing that pain explains behavior. So the behavior happens first — you jerk your hand away from the stove — then the pain tells you why you did that.
Anna Rothschild: Exactly. And if Deb is right, then that means that an animal’s behavior alone doesn’t say much about whether it’s conscious or not. She thinks it’s much more relevant to look at how their brains are wired.
Brooke Borel: I see.
Anna Rothschild: But to be clear, even though Deb and Heather disagree on this point — about the function of pain and what you can infer from it — they agree that pain is just one possible marker of consciousness. There could definitely be other ones — like Heather mentioned, maybe some animals don’t experience pain, but they experience feelings of hunger or curiosity. Pain is just the one that’s been studied the most, so that’s where a lot of this debate happens.
Brooke Borel: Well I am very curious where this conversation went when you brought these two guests together.
Anna Rothschild: Take a listen.
[MUSIC]
Anna Rothschild: Just to start, I’m curious, have you two met before?
Deb Brown: No. Hello, Heather.
Heather Browning: Oh hi. Nice to meet you.
Anna Rothschild: Just for the record, it was 5 in the morning for me, because that’s what happens when you book podcast guests in the U.K. and Australia and you need to talk to them from New York.
Brooke Borel: Geez. Well, sometimes you’ve got hard-hitting cephalopod questions that need answers; you’ve got to do what you’ve got to do.
Anna Rothschild: That’s right. We started off talking about the report by Heather and her colleagues — the one that found that cephalopods and crabs and lobsters are likely to be sentient and capable of feeling pain.
Anna Rothschild: Deb, I know you have some critiques about the type of evidence Heather and her colleagues have used in their cephalopod and decapod crustacean report. Can you share a little bit more broadly what those are here?
Deb Brown: Oh, well, I think it’s heavily weighted towards behavioral criteria and in our sort of understanding, behavior can be a sign of consciousness, but it isn’t constituentive of consciousness. And I think that what the criteria lack is attention to just all the work that’s been done in neuroscience in trying to sort of unpack the neural circuitry and the kinds of computations that have to be performed in order for a creature to particularly feel pain. I mean, I know there’s other kinds of consciousness, but we probably know more about pain than any other conscious state. So I guess I would like to have seen some more attention to those neurological criteria.
Heather Browning: Yeah, so I think one of the reasons that we didn’t go too deeply into the neurological criteria is just because what we came across was quite widespread disagreement between some fairly prominent neuroscientists about exactly what criteria there were. And so our worry was that if we were going to sort of put criteria in that would be satisfactory to the broad range plausible views on the table, that they were probably going to be too inclusive to be particularly guided at this point.
Deb Brown: Well, I think there’s sufficient sort of consensus that you need the cortical structures to be activated in order to feel pain. A lot of the disagreement actually comes from philosophers working in the field. But I think even if there is that disagreement, going instead to behavior is kind of stacking the deck in a certain way in favor of ending up with a criterion that’s too permissive, right, that lets in too many things in a somewhat nonrigorous fashion. And partly because pain can be dissociated from behavior. We know that nociception can be dissociated from behavior. So long as you’ve got these dissociations, then behavior is not going to be either a necessary nor a sufficient condition for the existence of pain in an organism.
Heather Browning: Yeah, I guess one of the things that struck me from what you’ve just said is this idea of necessary and sufficient conditions, because I don’t think we felt like anything we were establishing were necessary or sufficient conditions for consciousness. I think we saw them all as probability-raising markers, where absolutely any one of them individually is neither necessary nor sufficient, but the idea is the evidential picture that emerges for an organism that satisfies a large number of the markers, it just becomes more and more likely that the explanation for all of those is that they’re all pointing towards some consciousness rather than them all being explicable in like dozens of different ways.
Anna Rothschild: Heather described this as an “inference to the best explanation” approach. That’s a form of reasoning in philosophy where you take a set of observations and try to come up with the hypothesis that best explains them all.
Deb Brown: Yeah, I get where you’re going, but I think for it to be a valid inference to the best explanation, there has to be a sufficiently strong correlation between the behavior and the pain. And I think that behavior can only ever really be a sign of consciousness; it can’t be a constituent of cause.
Heather Browning: I mean, certainly we didn’t think that the behavior was constituent of a consciousness. I think we would see it as a downstream effect. And obviously then this is going to be based pretty heavily within some theorizing about the role that pain plays. You know what is the benefit of having pain versus just having nociception? What is that likely to facilitate for an organism? Presumably it was selected for some reason, and based in those kinds of theories, it’s looking for behaviors that are tied to that function.
Deb Brown: Yeah. Which is a bit problematic, if you have to assume that pain is the cause of behavior. There’s actually increasing amounts of neuroscientific evidence, which would suggest that pain isn’t a cause of behavior. I mean, I think its function is starting to be revealed as a bit more complex than that. You know, we are surmising that it actually plays more of an explanatory function rather than a causal function.
Anna Rothschild: Remember, Deb’s view is that pain is a kind of spotlight that comes on after the body has already reacted reflexively to some harmful stimulus — as a way of being like, “Hey, this is why your body just reacted that way.”
Brooke Borel: Right. So she’s pushing back on Heather’s assumption that, for example, those hermit crabs were leaving their shells because of the pain.
Anna Rothschild: Right.
Brooke Borel: So basically, they’re coming at this from two different perspectives — Heather is taking the behavioral psychology approach, and Deb is focused on the neuroscience, and those different starting points are leading them down different paths.
Anna Rothschild: Yeah, so far scientists haven’t managed to bridge that gap. I mean, part of the problem is that at this point there’s still so much we don’t know. And this question of how we detect animal consciousness kind of spans all these different disciplines — from psychology to neuroscience to philosophy to animal welfare — so it’s hard to even figure out how to approach it.
Brooke Borel: But in the meantime we still somehow have to make decisions about what kinds of rights these animals deserve.
Anna Rothschild: Yeah, so there aren’t easy answers.
Anna Rothschild: How complete an understanding of another creature suffering must we have before deciding to protect it? You know, where does the burden of proof lie? Should we assume animals are conscious unless proven otherwise, or vice versa?
Heather Browning: I think it’s going to be neither of those extremes. I don’t think we are going to be in a position where we should assume all animals are conscious or where we should assume none of them are unless we’re completely 100 percent convinced because I mean I think we are never going to be in a position where we can be 100 percent convinced. If we put the philosopher hat on, we’ve always got some level of skepticism. But yeah, even given that, when we think about the level of potential harms and benefits of making these errors, either over attributing or under attributing consciousness, the question becomes: What are the costs and what are the benefits of each of those things?
And that might be different in different cases. It might be different for different types of animals. So it’s going to depend on what kinds of animals we interact with, how we use them, what kind of harms are easily preventable in a cost effective way. And so all these sorts of things are going to play into perhaps where we set the evidential bar, at least for the purposes of our actions.
Deb Brown: Yeah, I would agree with Heather. I don’t think it’s a good idea to just assume that animals are conscious unless proven otherwise. You’re kind of on the slippery slope there to panpsychism. There are people who are pushing ideas, for example, that plants feel pain. Some people even go so far as to say that there’s consciousness at the level of cells because they’re assuming that you couldn’t have consciousness just appearing at some level of complexity in evolution. So it would have to be present there in a little bit, all the way through evolution. But there’s really not much justification for doing that. So I think we have to be able to draw the line somewhere. And then the real debate between us all is where that line is to be drawn.
[MUSIC]
Anna Rothschild: So, Brooke, I want to hear what you thought about this episode, but first I have a question for you.
Brooke Borel: Yeah.
Anna Rothschild: I’m curious if you have a guess about which participants in this conversation eat meat.
Brooke Borel: Well, I’ve shared a meal with you, so I know you do. I would say Heather definitely does not eat meat, and Deb, I don’t know, maybe?
Anna Rothschild: Close. So, I was the only meat eater in that conversation.
Brooke Borel: I see.
Anna Rothschild You’re right about Heather — she’s more or less vegan, actually. But Deb also doesn’t eat meat — just seafood, occasionally, but she’s even trying to cut.
Brooke Borel: But, I take it, not because she’s worried about fish’s feelings.
Anna Rothschild: No, she said it’s mainly for environmental reasons. And actually, she made an interesting point about that during one of our conversations: that, basically, no matter what she thinks about animal consciousness, she’s not saying that animals don’t need welfare protections. She just thinks there are lots of reasons animals are worth protecting, like to protect ecosystems and the environment, and all sorts of reasons. And that whether or not they’re conscious isn’t necessarily the most important question.
Brooke Borel: It’s like more of a philosophical question than a way to decide how we should treat animals.
Anna Rothschild: Yeah, exactly. I thought that was a really interesting point of view on Deb’s part. It’s interesting, too, that in practice, both Heather and Deb want a lot of the same things for animals, even though they disagree on what their inner worlds are probably like.
Brooke Borel: I guess that’s good, since we’re probably not settling that debate particularly soon.
Anna Rothschild: Yeah, and honestly, I left these conversations kind of feeling like maybe we can’t ever settle it? Not that I think scientists should just give up on it. I think it’s important — and also just super interesting — to see where else consciousness might show up in the animal kingdom and what it might be like for other beings on this planet. But even if we do manage to prove that certain animals are conscious, or sentient, or whatever, I don’t see how we can ever really know what it’s actually like to be them.
Brooke Borel: Right, what it’s like to sense the world with their bodies.
Anna Rothschild: Yeah, like even if we prove they have some conscious experience of pain or pleasure, we don’t know if it’s anything like ours. But as humans, all we have is ourselves as a reference point. So we’re always going to kind of be projecting our experience of consciousness onto other animals.
Brooke Borel: Oh, totally. Like, having personally done zero scientific studies on this, sometimes I’ll have a little moment with a bird and think, that creature is definitely conscious. I’m sure people who actually research this are more rigorous than me, but I’m just saying, it’s really hard to not project what we feel onto other animals because we just have no real way to know what it’s actually like to be them.
Anna Rothschild: Definitely.
Brooke Borel: Alright listeners, I want to hear what you think. Which animals do you think are conscious, and why?
Anna Rothschild: Send us an email at [email protected]. We would love to hear from you.
Brooke Borel: And that’s it for this episode of Entanglements, brought to you by Undark magazine, which is published by the Knight Science Journalism Program at MIT. Our amazing producer and editor is Samia Bouzid. This show is fact-checked by Undark deputy editor Jane Reza. Our production editor is Amanda Grennell, and Adriana Lacy is our audience engagement editor. Special thanks to our editor in chief, Tom Zeller Jr. I’m Brooke Borel.
Anna Rothschild: And I’m Anna Rothschild. Thanks for listening. See you next time.