I think this is a good question (and I see it’s well intended), but it seems to me that you’ve overinflated your point. I don’t think it’s accurate say there is a dark downside—rather, there’s just a reason for uncertainty.
Pointing out the number of shellfish (bivalves, to be specific) is potentially misleading if you don’t also add some information about what reasons we have to think that they might or might not be sentient. I think these are the most important things to know:
- Bivalves have no brains, at all. They have ganglia (nerve clusters) but no centre to their nervous system. In contrast, insects have (simple) brains).
- There is no behavioral evidence for pain responses (some will suggest there are, but the behaviors can be explained mechanistically).
+ Bivalves have nociceptors (which are necessary for detecting pain).
The lack of a centralised nervous system seems pretty crucial to me. Given that, I don’t think it makes sense to assume a very low degree of sentience. I don’t think there’s much reason to think that intensity of sensation scales this way at all (it seems more charitable to them to assume they have less diverse but still intense feelings). So I would treat it as “sentient or not” and put only a tiny probability on them being sentient, although not a 0 probability. That changes the framing from: “I think there might be a small amount of suffering here, and there’s a LOT of them” to “there is probably no suffering, but I’m unsure, and if I’m wrong then it would be huge”.
Indeed, my post was somewhat inspired by my wife Diana Fleischman’s discussion back in 2013 of whether it’s OK for ethical vegans to eat shellfish, given the uncertainty about whether their little ganglia carry any sentience; see link here.
My hunch as an evolutionary psychologist is that, given the extremely strong selection pressures on shellfish to resist being eaten by starfish, and their apparent use of all possible muscular effort and endurance to keep their shells closed when being attacked by starfish, if shellfish are sentient about anything, they’re most likely to be sentient about resisting starfish attacks, and being motivated to treat them as a negative experience.
I think this is a good question (and I see it’s well intended), but it seems to me that you’ve overinflated your point. I don’t think it’s accurate say there is a dark downside—rather, there’s just a reason for uncertainty.
Pointing out the number of shellfish (bivalves, to be specific) is potentially misleading if you don’t also add some information about what reasons we have to think that they might or might not be sentient. I think these are the most important things to know:
- Bivalves have no brains, at all. They have ganglia (nerve clusters) but no centre to their nervous system. In contrast, insects have (simple) brains).
- There is no behavioral evidence for pain responses (some will suggest there are, but the behaviors can be explained mechanistically).
+ Bivalves have nociceptors (which are necessary for detecting pain).
The lack of a centralised nervous system seems pretty crucial to me. Given that, I don’t think it makes sense to assume a very low degree of sentience. I don’t think there’s much reason to think that intensity of sensation scales this way at all (it seems more charitable to them to assume they have less diverse but still intense feelings). So I would treat it as “sentient or not” and put only a tiny probability on them being sentient, although not a 0 probability. That changes the framing from: “I think there might be a small amount of suffering here, and there’s a LOT of them” to “there is probably no suffering, but I’m unsure, and if I’m wrong then it would be huge”.
Hi Tristan—fair points.
Indeed, my post was somewhat inspired by my wife Diana Fleischman’s discussion back in 2013 of whether it’s OK for ethical vegans to eat shellfish, given the uncertainty about whether their little ganglia carry any sentience; see link here.
My hunch as an evolutionary psychologist is that, given the extremely strong selection pressures on shellfish to resist being eaten by starfish, and their apparent use of all possible muscular effort and endurance to keep their shells closed when being attacked by starfish, if shellfish are sentient about anything, they’re most likely to be sentient about resisting starfish attacks, and being motivated to treat them as a negative experience.