Yet one more add-on to the clarification email... it's my opinion that the more folks try to distance themselves, the more it becomes evident how similar we actually ARE. I can contrast and compare Ultra-orthodox Judaism with something seemingly incongruent as Amish. Comparative theology is truly fascinating and equally disconcerting at the same time. The destination (enlightenment, nirvana, heaven, etc) is relatively the same, yet the views along that journey can be so radically different. Scary.
My background in comparative theology is more Christian-Buddhist and Christian-Hindu than inter-Abrahamic, which is something of a shame. But the Maven's comment brings me, finally, back to one of the reasons this blog even exists: to post musings about things like interreligious dialogue, comparative theology, etc.
One of my pet areas of study is precisely this question of whether "the destination is relatively the same." This is, according to the typology I've laid out in previous posts (see here: 1, 2, 3, 4), a convergent pluralist stance. I'm sympathetic to this stance because it's where I started out, especially after reading the work of John Hick.
But I'm no longer a clear convergent pluralist. Divergent pluralistic arguments are pretty strong-- the strongest being that the assumption of a single soteriology is unwarranted given the phenomenological evidence. Are people who attain enlightenment experiencing the same thing as people going to heaven? How do we know this? Aside from the fact that the liberal wings of the great traditions seem to claim something like this (e.g., many paths up the same mountain to the same summit), what other evidence do we have? The phenomenological evidence seems to be more in favor of traditionalists/conservatives who insist on the radical difference between* the various soteriologies-- Buddhist, Christian, Hindu, Jewish, Muslim, etc.
Stephen Kaplan makes this case by viewing the problem through the lens of constructivist epistemology. One chapter of his Different Paths, Different Summits is devoted to exploring the question of whether ultimate human states (say, mystical experiences) share an underlying sameness. He concludes that they don't, but this irreducible diversity is no hindrance to his pluralistic vision. Perhaps he has a point.
S. Mark Heim's version of divergent pluralism is a strong caution against steamrollering diversity by placing so much focus on abstract commonalities. The problem with abstraction is that, once you've reduced a tradition to vague and general concepts like "ultimate reality," "salvation/liberation," etc., it's arguable that you're no longer talking about any given religion in particular. In Heim's view, this amounts to constructing a metaparadigm that is actually a form of crypto-inclusivism, constantly undermining any claims to pluralism.
Both of these writers bring good arguments to the table, and as a result, I've moved away from a pure convergent pluralism to what I hope is a more nondualistic stance. I can't concede everything to the divergent pluralists, because their arguments also contain some major flaws (I've discussed this in previous posts; see sidebar), but the issues they raise are too important to ignore.
*It goes without saying that there are myriad intrareligious differences as well.