John Hick's theory of religions is very interesting, and to many people these days it may seem most plausible. For him, the different religious traditions in the world have more or the same essence or core: they call people to change the fundamental orientation of their lives away from Self towards this ultimate reality, which Hick calls the Real. This change manifests itself in an ethical transformation that is more or less common to many religions: the person this reoriented lives a life of compassion, love, goodness, and so on.
But what about the fact that so many different religions describe God differently? And some religions are not even theistic at all—how can all these be essentially the same in reorienting people to the Real? Hick's answer is to adopt a kind of Kantian metaphysics and epistemological theory. On this view, reality in itself (called the noumena like realm) is utterly impossible for us to know. All we ever know is reality as it appears to us through the filter of our social-linguistic-cultural backgrounds; this is called the phenomenal realm, the realm of appearances. For Hick, all religions and philosophical traditions which attempt to describe the Real in itself fail, because the Real cannot be known. Their language is reinterpreted mythologically: their descriptions are not literally true, but instead are supposed to arouse certain reactions and dispositions in people.
Hick supposes that such a pluralist doctrine is preferable to exclusivist positions which claim their own religious tradition as definitively and ultimately true. He also thinks that such a pluralist understanding is also more conducive to toleration and dialog, because each tradition is not intrinsically superior to any other one. They are all getting at the same thing in the end, so this understanding ought better to foster collaboration and friendly dialog.
But is all this right? Gavin D'Costa begs to differ, and his arguments are very convincing. In The Meeting of Religions and the Trinity, for example, he argued forcefully that Hick's position is just as much exclusivistic as those positions he decries as intolerant and hopeless. For consider Hick's Kantian epistemology: by denying that any religious tradition can legitimately claim knowledge of the Real, he effectively tells them they are all actually false; he judges them all as false, and props up his own Kantianism as the true alternative, in good exclusivist fashion. Thus pluralism turns out to be a kind of Enlightenment exclusivism, not any more tolerant or conducive to dialog than an exclusivist Christianity would be.
D'Costa also argues persuasively that Hick's pluralism is imperialist and intolerant, despite its claims to be otherwise. For Hick effectively denies the religions of the world the right to exist on their own and in their own terms, if they insist on being genuine revelations of the real truth. Rather, theological language has to be reinterpreted in instrumentalist, mythological fashion, or else it is rejected as obviously false. Effectively Hick is telling everyone else how properly to understand their own religious traditions—as he does, as an Enlightened modernist Westerner!
One final argument ought to be mentioned too. Hick's claim that the Real in itself is unknowable ultimately reduces to agnosticism, because we can never get beyond the false appearances we confront to get the truth of the matter. If the Real is unknowable, then different religious forms and traditions are just a matter of taste; what ultimately matters is ethics and right living. But D'Costa, drawing from Alisdair MacIntyre, notes that ethics doesn't make any sense when it is divorced from a particular picture of the world. For example, the Christian notion that we are to love our enemies makes no sense and is impossible to justify apart from the affirmation that God himself, as ultimate reality and goodness itself, also is indiscriminate in his love. If an ethical system or theory cannot be justified by appeal to a true metaphysics, then ethics is just a matter of taste and sentiment, lacking objective validity. In that case, there can be nothing wrong with remaining an exclusivist, since the pluralist's own revulsion at the thought has no basis in an objective moral reality!
So despite the appearance of being tolerant and conducive to dialog, D'Costa demonstrates that Hick's pluralism is actually oppressive, exclusivist, and ultimately nihilistic about ethics.