A follow-up to part one and part two. I see three layers in debates over political or social issues: the bottom layer is some fundamental issue that could be classified as one of Haidt's moral foundations, or one of Kling's three axes; the middle is the rhetoric used to defend the bottom layer; and the top layer is the conclusion about a specific situation.
For example, one might oppose a new gun-control measure (top layer) using arguments (middle layer) that are based on one's aversion to any restriction of personal liberty (bottom layer), although the arguments might not acknowledge the foundation at all. When I observe the use of rhetorical devices to defend a single foundation while totally disregarding others, it sometimes strikes me as disingenuous and sometimes as subconscious (and I'm not sure which is worse). Either way, the arguer seems to be using whatever arguments are at hand, even if these arguments are deeply flawed.
Once we accept the importance of multiple foundations, there is all kinds of potential for reasonable debate. It becomes a big mess when similar rhetorical devices are used for very different purposes: either to defend a single foundation and close off debate, or to try to find the most reasonable means of balancing multiple foundations in a given context. My instinct is always to focus on the middle layer (the argument itself), whatever the motivation may be for making the argument, and to criticize a faulty argument--one that doesn't make logical sense, is biased in some concrete way, disregards some consideration, etc. (BTW I'm not terribly comfortable with the "layers" analogy, since it implies a unidirectionality that isn't really present, but I don't have a better alternative right now.)
Kling and Haidt suggest focusing on the foundations in many of these cases where debate has been unproductive. I think that their models are tremendously useful in understanding debate, but I am not optimistic that this understanding can improve debate, except perhaps in marginal cases.
Take gun control again. This is a good one to use as an example because so many people on both sides get hot-headed about it. The reasonable debate is over what measures can be taken to improve public safety with relatively little infringement on the rights of gun owners, and there is in fact some fairly civil debate over this question. At the same time, some opponents of gun control seem to be totally focused on their own personal liberty, to the exclusion of any other consideration. This focus can lead to flawed reasoning at the middle layer, such as a refusal to acknowledge any evidence indicating that a specific gun-control measure can be effective at reducing violence in a specific context. On the other side, some advocates of gun control focus solely on victims of gun violence, and from there embrace the view that restricting access to guns is necessary and sufficient for reducing violence in every context, which is just as unreasonable and indefensible as the opposite extreme.
The problem I see is that, even if I feel certain that someone is doing something like what I describe above, I don't see a way to point that out in a way that that person is likely to accept. Will it be any more useful to point out that someone is solely focused on personal liberty than it would be to point out that someone is disregarding or misinterpreting evidence? Once in a while, maybe; but most of the time, I would expect the accused to be defensive on either score. In a sense it's easier to defend against the accusation that one is focusing on one foundation to the exclusion of all else. The gun-control opponent can claim to care about victims of violence and maintaining public safety, and then argue that gun control doesn't really contribute to public safety, even if such an argument is necessarily flawed. Criticizing the unreasonable argument instead has the advantage of being more concrete. Biased interpretation of evidence, for example, can be pointed out in a way that is hard to deny. It still doesn't usually help, because someone can find all sorts of excuses for disregarding a perfectly reasonable argument. The question, again, is whether someone inclined to disregard the reasonable argument is any more likely to accept the claim of undue focus on one foundation.
To anyone with any inclination to meta-rationality, Haidt, Kling, and others have provided some very valuable tools. "The Joneses," as I referred to them in a recent post, are meta-rational but are otherwise diverse in their views and priorities. They can better understand their own mental processing using models from Haidt et al, and debate and discussion among the Joneses can be much more productive. In dealing with the Smiths, on the other hand, the Joneses might simply be better able to articulate the source of their frustration.
In that same post, I raised the possibility that trust is the real barrier to productive debate. Say Smith values personal liberty highly, and because of that is attracted to faulty arguments opposing gun control. Jones tries to make Smith aware of this, but Smith doesn't trust anything Jones says because Jones does not value personal liberty as highly as Smith. Smith might be vaguely uncomfortable with Jones's argument, or he might pointedly think that Jones is somehow trying to trick him, even though he is unable to identify the nature of the trickery. Smith is likely to have a source he can turn to, like the NRA, to back up his suspicions, even if it takes more of the same faulty arguments to do so. Perhaps it takes a libertarian Jones to get a libertarian Smith to be more open-minded: someone who can say, "I agree with you about the importance of personal liberty, but...." A problem there is that libertarian Jones is likely to take a dim view of most forms of gun control and so would not perceive much value in getting Smith to moderate his view a bit. The real value would be in getting Smith on the same page as the Joneses, rationality-wise. So maybe the thing to do is to is to get all the Joneses to agree to try to influence the Smiths with whom they are most closely allied in respects other than rationality itself. I'll chew on that one for a while.