Hey, I’m all in favor of factory-manufactured meat, if it can be made to taste as good as the naturally grown variety, but I’m not going to stop eating meat until it happens. My criteria are basically intelligence based, and the first animal I’d give up eating, if I were going to give up any,s would be pigs, but I still occasionally have pork. I don’t feel that badly about eating cattle–they just don’t seem that bright to me. And the question of whether or not they’re better off living a short life, and then being slaughtered, than never having existed at all is one that, as noted, is purely subjective and unresolvable in any ultimate sense. I know that I’ve seen some pretty happy looking cows on the hillsides overlooking the Pacific in northern California. I can think of worse lives.
By the way, Phil should be aware that marsupials are mammals. The distinction is placental versus non-placental mammals. And there are people (probably some of those “bitter,” out-of-work folks) in this country who eat possum, and armadillo.