Thank you both for these answers, this is helpful!
It sounds like it is useful to distinguish two possible ways of implementing a welfare market:
A farmer is paid to change the welfare of their animals from negative (it would be better if they had never existed) to positive (it is better that they get to exist).
A farmer is paid to change the welfare of their animals from negative, to less negative, but the animals still lead net-negative lives overall.
I can see how on pure consequentialist grounds the first case would be good, and avoid the problem I was asking about. Although I expect a lot of vegans who have a principled objection to animals being treated as property will object to this, if increasing quantity of farmed animals is explicitly viewed as a positive outcome of the policy. I would certainly have reservations about it.
On the other hand, the second case seems like it does carry the risk I was asking about. We should expect the quantity of animals farmed to increase in a way that might outweigh the gain in welfare per animal (whether or not it does will I think depend on complicated economics things like the slopes of supply and demand curves?)
Thank you both for these answers, this is helpful!
It sounds like it is useful to distinguish two possible ways of implementing a welfare market:
A farmer is paid to change the welfare of their animals from negative (it would be better if they had never existed) to positive (it is better that they get to exist).
A farmer is paid to change the welfare of their animals from negative, to less negative, but the animals still lead net-negative lives overall.
I can see how on pure consequentialist grounds the first case would be good, and avoid the problem I was asking about. Although I expect a lot of vegans who have a principled objection to animals being treated as property will object to this, if increasing quantity of farmed animals is explicitly viewed as a positive outcome of the policy. I would certainly have reservations about it.
On the other hand, the second case seems like it does carry the risk I was asking about. We should expect the quantity of animals farmed to increase in a way that might outweigh the gain in welfare per animal (whether or not it does will I think depend on complicated economics things like the slopes of supply and demand curves?)