Moral relevance of cognitive complexity, empathy and species differences in suffering

I qualify two criticisms made by commentators on Chapman & Huffman’s target article. Responding to the view that differences between humans and other animals are irrelevant to deciding how we should treat other species, I point out that differences between any species in their capacity to suffer are morally relevant. And in response to the claim that suffering is the sole criterion for the moral treatment of animals, I argue that cognitive complexity and a capacity for empathy also have moral relevance to the extent that they influence suffering