John Mark Reynolds’ response has helped me to clarify where I think he and I are disagreeing on the torture question.
If you only consider consequentialist principles, you can’t get an absolute prohibition on anything except the principle that we should seek the best consequences. So to get a moral ban on all torture, there better be some deontological principles at stake. The question is whether those deontological principles themselves are absolutist.
I happen to think the only deontological principle that is absolutist is the moral claim that we ought to give due honor to God and follow him in whatever ways are best for doing so. There are many ethical principles beyond that, and most of them apply most of the time. Some of them apply almost all the time and would require crazy hypotheticals to find exceptions (or very weak cases with moral principles about matters that involve vague concepts occurring along a spectrum, such as consent and coercion, harm, or what someone’s motivation and desires are in doing an act).
But to answer your question, I think the deontological principle behind JMR’s opposition to torture is his principle that it’s always wrong to coerce someone, a principle I’ve questioned. He doesn’t think it’s always wrong to cause pain or to cause pain that someone remembers. He doesn’t think it’s always wrong to cause harm, even permanent harm, knowing full well that one is doing so. He does think it’s wrong to cause harm for the sake of causing harm without some higher purpose, but he doesn’t think such a higher purpose can be merely getting information that will lead to better consequences when the causing of harm is done to violate someone’s ability to consent to giving up that information. So it’s mainly an issue of consent to choose to speak when one wants to and to refrain from giving information when one doesn’t.
As I’ve said along the way, I think the problem with that argument is that consent and coercion come along a spectrum, and weaker versions of coercion undermining consent can be morally correct under the right sorts of circumstances. When the consequences increase in their badness, avoiding them might require undermining consent to a stronger degree than is normally moral. That’s why I think torture isn’t in principle wrong. JMR has a more absolutist view about that principle. We both take it to be deontological, because neither of us thinks slightly better consequences for a serious undermining consent are enough to justify it. But he takes it to be absolutist, whereas I think there could be circumstances where undermining someone’s consent via coercion to a great degree can be morally all right, as long as those consequences are extremely serious.
So I’m not sure the disagreement is really meta-ethical. It’s more on the level of normative ethics, I think.