John Schwenkler, who blogs here, wrote, in a comment to this post:

[It’s] hard to see [given what I characterized as the “traditional” view of our place in the cosmic scheme of things — ed.] why we, unlike other animals, should be under an absolute (or even less than absolute) obligation not to consume members of other species. Put differently, there seems to me to be a slippery slope between a vegetarian ethic and the desire to “‘manage’ the natural world in order to make it over into an edenic pleasure garden where all creatures are protected” that is not present when one’s position on the rights of other animals is centered on the demand that they be raised in ways that promote their own flourishing, slaughtered humanely, and more generally thought of and treated with reverence and respect. Humanist “exceptionalism”, in other words, lends itself toward “well-meant benevolence” in much the same way as it can be used to excuse the mistreatment of other species, while what you’re (rightly) calling the “traditional view” at once permits us to feed on other animals in ways similar to those in which they are nourished by each other, demands that we do so in a restrained and respectful way that befits our natures and theirs, and prohibits us from trying to manage their environments and make them into something they aren’t.

I think Clark’s response to this objection would be that refraining from killing and eating animals is not “well-meant benevolence” in the presumptuous sense of aiming to manage the biosphere. Earlier in the book he says that, whatever else may be true about the metaphysical status of us or our animal kin, it surely must be wrong to be the cause of avoidable harm.

Clark writes (from an excerpt here):

Consider then: it is not necessary to imprison, torture or kill animals if we are to eat. The laborious transformation of plant proteins into animal protein, indeed, is notoriously inefficient, and wastes a great deal of food that would greatly assist human beings in less carnivorous places. It is not necessary for us to do this: I say nothing of what may be necessary for the Eskimos, for whom the orthodox display a sudden, strange affection when confronted by zoophiles (though the health of Eskimos might be better served by supplying plant-food). It is not necessary for us, and our affection for other human beings would perhaps be better shown by ceasing to steal their plant protein in order to process it into a form that pleases our palates.

In other words, refusing to eat meat is not an arrogant attempt at managing the natural order, but a refusal to be the cause of other creatures’ suffering when it isn’t necessary. Fundamentally, it’s about leaving them alone.

This isn’t to say that Clark wouldn’t regard traditional animal husbandry as an improvement over our current practices. But even here he would question whether even “humane farming” really does respect the animals’ natures. Just to mention one point, even humanely raised animals are painfully slaughtered well before the end of their natural lifespan.

Utilitarians like Peter Singer say that killing an animal (“humanely”) and replacing it with an animal that is, at least from our point of view, pretty much identical, can result in a net gain in utility. So the animal is not wronged if we kill her. But Clark wouldn’t go along with the idea that killing an animal doesn’t count as a harm. At least from the animal’s point of view it would seem to make a difference whether she lives or dies. So, I think there’s still a case to be made that unnecessary (even if “humane”) killing is, at least prima facie, unjustified.

It’s sometimes said that, if we didn’t raise them for food, domesticated farm animals wouldn’t exist. Whether or not that’s true, it surely doesn’t follow that we can do whatever we like with them, anymore than you can torture or murder your child just because he wouldn’t exist if not for you. Though, if it is true, it may speak to John’s original point: if farm animals are, in a sense, artifacts of human intervention, then it can’t be interference in a natural process if we stop killing them for food. Besides, if we’re really concerned that our domestic cattle, pigs, and chickens might become extinct, we could always set up animal preserves to make sure that their kind will be perpetuated.

Of course, it would be foolish to expect an act of human forbearance on that kind of scale anytime soon, which is why I personally would be happy just to see a large-scale shift to more traditional methods of farming. And there are plenty of self-interested reasons for human beings to start treating farm animals better (the environmental and health costs of industrial meat chief among them).