I think this is a good article and attacks some assumptions I’ve thought were problematic. That being said, I think it’s worth elaborating on the claim that intelligence scales with moral worth. You say:
“Furthermore, it certainly is not the case that in humans we tend to associate greater intelligence with greater moral weight. Most people would not think it’s acceptible to dismiss the pains of children or the elderly or cognitively impaired in virtue of them scoring lower on intelligence tests.”
This seems true, and is worth further discussion. Most famously, Peter Singer has argued in Animal Liberation that intelligence doesn’t determine moral worth. It also brings to mind Bentham’s quote: “The question is not, Can they reason?, nor Can they talk? but, Can they suffer?” We don’t think children have less moral worth due to their decreased intelligence, nor do we think that less intelligent people have less moral worth–so why should we apply this standard to animals? This is why Singer has argued for equal consideration of interests between species. What does this imply, then, about how we should determine the interests of animals?
Perhaps, we may try to count the neurons involved with pain, pleasure, and other emotions–rather than neurons as a whole—and use this as a metric for moral worth. This isn’t perfect, it still has many problems, but would probably be better than other approaches.
Amazing news! Does anyone know what percent of pigs spend their in gestation crates? I’m able to find data on overall population numbers, but I can’t find what percent of them become pregnant.