Trying to get to the bigger moral picture
Jeff McMahan's recent piece in the New York Times has provoked a lot of discussion (including two pieces here). He argued that just as it is bad for animals to suffer at the hands of humans, so is it bad when they suffer in the wild. Moreover, since there are vastly more animals in the wild than in captivity, this might be a much bigger issue. McMahan illustrated the problem by suggesting that if there were some way to eliminate carnivorous animals from the planet without messing up the ecosystem (a big if), then it would be very important that we do so. This example was presumably designed to show how the moral claim that it is bad for so many animals to suffer could be made practical, but it ended up muddying the issue a lot, as many people focused on this hypothetical rather than the big issue.
