Here's one vision of the future of meat: We manufacture it from stem cells in giant "bioreactors" of the sort you might find in a modern pharmaceutical factory. The cells come from a contented pig that lives in the yard outside the village meat factory, where technicians sometimes poke it with a biopsy needle, and meat-eaters with quiet consciences give it a pat on their way to buy a cultured piece of it.

That vision, more or less, is fleshed out in a paper published in the June issue of Trends in Biotechnology by philosopher Cor van der Weele and biotechnologist Johannes Tramper, a pair of Dutch researchers from the University of Wageningen. Both describe themselves as "modest" meat-eaters, concerned