There are several theological approaches to dealing with the problem of religious plurality, that is, how to deal with the fact that there are multiple truth claims made by others who seem very sincere. These truth claims are often exclusive. The evangelical and Mormon conversation typifies one response to the problem, that is, simply maintaining strict exclusivism. The best that can be done in this model is attempting to understand the other position thoroughly while maintaining that the end of the day the other position is just not a path to God. Though the other party may be sincere and well-meaning, there can only be one true path to God. This position has several advantages, among which are that it is simple, straightforward, and in a not so obvious fashion perhaps more respectful than the other possible positions because it recognizes that the other side is trying to claim an absolute truth which isn’t the same as your own. This model of conversation envisions an eventual total replacement of the other side by the one true way.
But there are other ways too. In Roman Catholic theology it is common to think of other religions as containing ‘anonymous Christians’ who have access to real grace in their own religious traditions. While Catholicism maintains that it has the clearest path to God and the most truth, it argues that there are sincere believers in other traditions that despite their traditions are, in a real sense, making their way to God. So it is that Karl Rahner can argue that other religions are ways of salvation, if not as bright and well-marked as the Catholic way, and even if the individuals in question are in reality being saved by Christ even if they don’t agree. This way has the advantage of approaching the other as possibly, in a true sense, approaching God and therefore listening closer, but all the while thinking that you are still most correct.
In liberal Protestantism there are generally two approaches that can be taken. One is that world religions are all mutually valid ways of approaching God- that is, different paths up the same mountain. Some arguing that this position is too arrogant in assuming that someone has access to seeing the whole mountain while others do not (those who insist their way is truly exclusive, for instance) and that there is but one peak argue that there are multiple mountains with multiple peaks. If a Buddhist expect nirvana and a Mormon the Celestial Kingdom, a good Buddhist will get nirvana and a good Mormon the Celestial Kingdom, exactly as they expect and desire. Naturally this approach creates the greatest openness to hearing others speak and completely eliminates the desire to convert the other.
I argue that it is best to be clear and straightforward about what our biases are. Obviously if we did not think we had the best way to worship God, we’d do it the way that we did think was best. The danger is that conversations with those very jealous about the exclusiveness of their truth claims often quickly become frustrating as each side, rather than being able to have open conversation, is on constant guard against giving too much ground while attempting vigorously to convert the other. I have seen too often conversations between evangelicals and Mormon degrade into a mutual play act, in which one side recalls ‘tips for evangelizing’ and the other resorts to bearing his testimony. Both sides walk away frustrated and having gained nothing whatsoever. Is there a way to engage in real conversation? Only if there is a modicum of danger involved, that is, an allowance of the possibility of changing minds, if even a little bit.