I’ve had a few thoughts about this recently (well, I’ve had a post drafted about point 3 for a while, but I don’t think there’s enough in it to warrant a whole post).
1. I think r/K-selection can tell a lot the closer a species is to our own. For example, I don’t think most rodent brains and development are so different from our own that we should expect them to process pain much less intensely than us, including at corresponding developmental milestones. This is a bad sign for rodent welfare.
2. However, invertebrates are very different from us, so we should be careful extending to them.
3. I think these results only really apply at equilibrium. Since populations are not in general at equilibrium, and my prior is that a change in conditions is in expectation bad for individual welfare, since their genes are being optimized for a given set of environments (related to the observation that there seem to be more ways for things to go wrong than for them to go right), this would be a reason to expect average welfare to be lower than you’d expect at equilibrium. If your prior was 0 at equilibrium, it should be negative outside equilibrium.
4. However, I also suspect there’s an argument going in the opposite direction (is it the same as the original one in the OP?): animals act to avoid suffering and seek pleasure, and the results might better be thought of as applying to behaviours in response to pleasure and suffering as signals than directly to these signals, because evolution is optimizing for behaviour, and optimizing for pleasure and suffering only as signals for behaviour. If we thought a negative event and a positive event were equally intense, probable and reinforcing *before* they happened, the positive event would be more likely to continue or happen again after it happened than the negative one after it happened, because the animal seeks the positive and avoids the negative. This would push the average welfare up. I’m pretty uncertain about this argument, though.
To illustrate a bit further, suppose individuals from a species are equally likely to encounter a given harm A or a given reward B for the first time, and these are equally intense for the animals, and the animals spend as many resources to avoid A as they do to seek B. After the first encounter with each of A and B, the reward B becomes more likely (immediately by reflex or in the future due to learning). Would this imply the species is not at equilibrium and evolutionary pressures should force them to spend relatively more resources on avoiding A than on seeking B? If not, this is a good sign for average welfare.
I’ve had a few thoughts about this recently (well, I’ve had a post drafted about point 3 for a while, but I don’t think there’s enough in it to warrant a whole post).
1. I think r/K-selection can tell a lot the closer a species is to our own. For example, I don’t think most rodent brains and development are so different from our own that we should expect them to process pain much less intensely than us, including at corresponding developmental milestones. This is a bad sign for rodent welfare.
2. However, invertebrates are very different from us, so we should be careful extending to them.
3. I think these results only really apply at equilibrium. Since populations are not in general at equilibrium, and my prior is that a change in conditions is in expectation bad for individual welfare, since their genes are being optimized for a given set of environments (related to the observation that there seem to be more ways for things to go wrong than for them to go right), this would be a reason to expect average welfare to be lower than you’d expect at equilibrium. If your prior was 0 at equilibrium, it should be negative outside equilibrium.
4. However, I also suspect there’s an argument going in the opposite direction (is it the same as the original one in the OP?): animals act to avoid suffering and seek pleasure, and the results might better be thought of as applying to behaviours in response to pleasure and suffering as signals than directly to these signals, because evolution is optimizing for behaviour, and optimizing for pleasure and suffering only as signals for behaviour. If we thought a negative event and a positive event were equally intense, probable and reinforcing *before* they happened, the positive event would be more likely to continue or happen again after it happened than the negative one after it happened, because the animal seeks the positive and avoids the negative. This would push the average welfare up. I’m pretty uncertain about this argument, though.
To illustrate a bit further, suppose individuals from a species are equally likely to encounter a given harm A or a given reward B for the first time, and these are equally intense for the animals, and the animals spend as many resources to avoid A as they do to seek B. After the first encounter with each of A and B, the reward B becomes more likely (immediately by reflex or in the future due to learning). Would this imply the species is not at equilibrium and evolutionary pressures should force them to spend relatively more resources on avoiding A than on seeking B? If not, this is a good sign for average welfare.
I’ve elaborated on point 3 here.