(Philip E. Devine, "The Moral Basis of Vegetarianism," Philosophy 53 [October 1978]: 481-505, at 491)
Note from KBJ: Devine's argument takes the following form:
1. Either the vegetarian argues on utilitarian grounds or the vegetarian argues on nonutilitarian grounds.The argument is valid (i.e., truth-preserving), and the first premise is true, but the second premise is false. Devine seems to think that if humans cease eating meat, they will derive no pleasure from eating. But not eating meat doesn't mean you get no pleasure from eating; it means, at most, that you get less pleasure from eating. Think of the difference between eating a hamburger and eating a veggie burger, for example. It is not as though the latter produces no pleasure! So the choice is between inflicting terrible pain and deprivation on animals and getting slightly less pleasure from eating. It's pretty clear that utilitarianism supports vegetarianism. Certainly Devine has not established that it does not.
2. If the vegetarian argues on utilitarian grounds, then vegetarianism is unsupported.
3. If the vegetarian argues on nonutilitarian grounds, then vegetarianism is unsupported.
4. Either vegetarianism is unsupported or vegetarianism is unsupported (from 1, 2, and 3, constructive dilemma).
5. Vegetarianism is unsupported (from 4, tautology).