Having complained about careless editing, I want to stress that Heim's basic argument is very powerful. So far comparative religion has been done using one of three models. There is only one true religion, all others are false (EXCLUSIVISM). Other religions may be effective as channels of truth (INCLUSIVISM). Every religious tradition "provides its own separate and independent means to attain the one religious end" (PLURALISM, p.3).
Heim offers us a quite different model. Each religion has its own religious aim, and we can respect its own claim to be the means to attain that aim. "Different religious aims are profoundly important, if we once suppose that they relate to distinctly different religious ends" (5). Thus a Christian can respect a Buddhist claim that it offers the only way to attain Nirvana, and at the same time explain that he or she has no inclination to lose all desire (based on an argument by J.A.DiNoia, 4). I would add that Zen Buddhism offers a way to experience satori through the discipline of zazen. TM offers a way of attaining peace of mind through constant repetition of a mantra. And one form of Hindu bhakti by chanting certainly frees one from concern about one's own personality.
The advantage of this approach is that it allows "the fullest legitimate recognition of the distinctive qualities (those that finally resist assimilation) of the positive religious aims of other faiths" (6). It also enables us to recognize that we cannot fully grasp the experience of another person's religion except from the inside (23, 27, 221)
The next move is to explain that no other religion offers us Christian salvation. Which Heim defines in a very specific way as "the human fulfillment that Christians believe is offered to us by God through Christ" (8). "Salvation is communion with God and God's creatures through Christ Jesus" (19, 49). Christian salvation is therefore relational (59, 124, 235), and this communion is with God as a "social trinity" (61, 132, 175, 284). And obviously no other religion offers that as their end. With this definition of Christian salvation Heim can still recognize the "different formulations in the Eastern Orthodox, Roman Catholic, and Protestant confessional traditions" (67).
Heim is postmodern in saying that "There is no 'metatheory,' no neutral place that allows us to judge from above the religions rather than among them" (6). He also adopts a model of God's Openness (77, 247, 263, 265, 267, strangely without even mentioning the huge importance of Clark Pinnock ed., The Openness of God, 1994).
Once it becomes clear that religions (and I would add ideologies) have different ends, which we can understand without wanting to attain them, we can avoid the perils of exclusivism, inclusivism, and pluralism (3), which have bedeviled the study of comparative religion (291-293). Heim wants to say that the various "religious traditions are part of God's providential purposes" (291), but he does not clarify how or why this should be so. I would argue that God allows us 23 ways to reject the love of God, but only Trinitarian Theism (Creative Love Theism) offers us a way to experience that love and explain how it works (as argued in God of Many Names).
Reply to a response to the above review
Doug Harink is right that my 23 alternatives (a very rough way of setting out a natural history of different kinds of religious explanation) are not rejections of the love of God. C.S.Lewis' story of the warrior who fought for the god Tash still had his heart in the right direction. I should have said that the 23 alternatives are different from our Trinitarian Theistic explanation. But no one is saved by a correct explanation.
I do not dismiss Heim's idea that religions are part of God's providential purpose, but I view the providential purpose in a different way from his attempt at syncretism. God allows us to try out all sorts of explanatory models (these should not be confused but be kept distinct), but if we are really wanting to love and be loved then Trinitarian Theism is the only explanation that works. Many people have their heart in the right direction but live without assurance because they are stuck with a wrong explanation. The function of our churches of the Spirit is to give the assurance that people so badly need (as in 1 John).
I should also have added that although understanding and adhering to our Creative Love Theism model does not save us, it is certainly true that preaching the good news of the model certainly helps people to look to the Lord in faith.