A second vegetarian strategy is simply to reject as immoral the balancing of animal pains against human pleasures. Thus John Harris's reply to the Benthamite defence of meat-eating is quite simply: 'Those who use it are saying that they think more about their stomach than their morals, and so a moral argument will probably not affect them'. We can call this move the deontological stop.
Deontological stops are not uncommon in philosophical discussions of moral questions. Perhaps the best known is in G. E. M. Anscombe's outburst: 'If anyone really thinks, in advance, that it is open to question whether such an action as procuring the judicial execution of the innocent should be excluded from consideration—I do not want to argue with him; he shows a corrupt mind'. And it may not be possible to avoid them without giving up the discussion of practical issues altogether or claiming, implausibly, that our arguments could have convinced Hitler or Stalin. But Anscombe could at least count on a certain aversion to judicial murder on the part of her audience. For a vegetarian to employ a deontological stop against those who defend the eating of meat would be to guarantee that vegetarian views will remain, and deserve to remain, the exclusive property of a sect.
(Philip E. Devine, "The Moral Basis of Vegetarianism," Philosophy 53 [October 1978]: 481-505, at 487 [italics in original; footnotes omitted])
Note from KBJ: Devine is a good philosopher, but here he conflates two issues. The first issue concerns the grounds of one's abstention from meat. There are absolutist deontologists who believe that certain acts are not only intrinsically wrong (i.e., wrong in and of themselves, independently of their consequences), but absolutely forbidden. In other words, no amount of good procured or evil prevented can justify those acts. Fiat justitia, ruat cœlum. Someone might hold that it's absolutely wrong to eat meat, just as someone might hold that it's absolutely wrong to torture, lie, or kill the innocent. This is an eminently respectable position, though it is far from universally held. The second issue concerns the persuadability of those who are not absolutist deontologists. If I, an absolutist deontologist, am trying to persuade you, a consequentialist or a moderate deontologist, to stop eating meat, I will have to show you that the consequences of eating meat are worse than the consequences of not eating meat (and significantly so, if you are a moderate deontologist). In short, Devine conflates (1) having grounds for one's own belief and (2) being able to persuade others to share that belief. I can have grounds for my belief even though those grounds won't persuade someone who endorses a different normative ethical theory. To persuade X, one must use only premises that are accepted by X. One need not oneself accept those premises.