It is conceivable. No doubt a band of astute theologians and philosophers could modify the "core doctrines" of Christianity enough to generate a materialist Christianity. Indeed, we have Mormonism. It is not my goal in this post to generate, or even attempt to generate, a materialist Christianity. Rather, my point is to ponder what that conceivability means for Christian revelation itself.
Let us posit the following, then: Given enough time and dialectic, one could adhere to any version of Christianity one liked. Surely all the materials of the faith and reason could be conscripted to support any "theory" of Christianity. The problem, however, is that a faith so radically open to revision and "re-envisioning" is unsustainable. It is a chimera. It is like a chair that could swap or lose any and all of its properties at whim (given enough time and dialectic), even its materiality. After so much "de-essentialization", however, in what sense can we speak of 'it' as a chair, or even as 'any thing' at all?
It is not my task as a Christian to devise clever, new ways to "reconcile" the Faith with the complexity of the human psyche, of ongoing scientific research, pluralistic and interreligious dialogue, etc. Indeed, as far as I know, it may be within the bounds of the deposit of faith to believe in a materialist Christianity (though, of course, at that point neither Christianity nor materialism would resemble themselves any more). It is not my Christian duty to devise or revise struts for the Gospel, but rather to accept the Gospel as the divinely revealed will of God.
The trouble, though, is that if this "revelation" is so endlessly mutable as to accommodate everything, and to assert nothing, then there is no-thing for me to accept by faith. The ongoing understanding of the Gospel must have a character of the same nature as its foundation––namely, divine revelation––, or the revelation cannot be ongoing (or, abiding).
It dawned on me as I pondered this last night that this is the reason I am a Catholic. The teaching of magisterial infallibility is as scandalous as the Gospel which would root all redemption in the life and death and resurrection of a wee Jew some two thousand years ago in a backwater. Hans Küng once mused how absurd it is for the Catholic Church to claim magisterial authority ultimately hinges on the bishop of Rome. A man in Rome! A man! In Rome, of all places! What a grotesque historical accident papal infallibility is (according to Küng). Yet I immediately realized how absurd (and grotesque) it is for the Church also to claim redemption and the fulness of wisdom ultimately hinges on the birth and death of Jesus Christ. A man in ancient Palestine! A man! In Bethlehem, of all places!
Thus it seems to me that the Catholic Church alone has a suitably scandalous self-consciousness of Her mission as the pillar and foundation of the truth.
It is not my duty as a Christian to "figure out" the contents, defects, excesses, deficiencies, etc. of the Faith. It is, rather, my duty simply to heed to voice of the Church when She speaks. If God has not provided a way for me to detect that voice with scandalous sacramental precision, then God has not provided me with a way accept the primal scandal of His Incarnation. In order for Christianity to salvage its claim to be a consistent universal religion, there must be something in every age and for every person which makes the immediacy and "provincialism" of the Church's preaching as scandalous as the scandal of the son of a carpenter pinning all of Israel's hopes on Himself. The dogma of papal infallibility fulfills that role.
Yet this is not an argument for idealized integralism. There has always been ambiguity in the life of the Church. Otherwise, what need for faith, hope, and love? The original kerygmatic density of the Gospel (in the early Church) has been teased out over the centuries into an intricate system of doctrine and piety (dogma and worship). As the orthopraxic structure of the Church became more refined and complex, the magisterial order became more pronounced and self-conscious. This is no mere coincidence. In the earliest days, there was the challenge of feuding bishops, an unspecified canon, linguistic confusion, and so on. Yet there was also something so powerfully unique and coherent about the Gospel that those extrinsic cultural assaults only made the Church's self-consciousness that much more pronounced and articulate. As time passed, and more and more dogmas became "taken for granted" (in so far as they were seen to be de fide), there way a corresponding rise in the extrinsic difficulties posed to the Church: unevangelized nations, slavery, freedom of conscience, imperial collaboration, scientific discoveries, interreligious challenges, hermeneutic spirals, textual criticism, etc. One of the most vivid signs of Providence for me is precisely this concomitant rise in magisterial order and doctrinal clarity. The more universal the Church has become, the more organically centralized She has become––and vice versa.
Some sects would only accept a pre-Constantinian Christianity. Others would accept only a post-Lutheran Christianity. Others still would accept only a pre-Florentine Christianity. And others still would accept only a pre-Vatican II Christianity. In other words, sects, unlike the Church, accept only a golden age, or some golden facets, of the Church's heritage. Alas, there has never really been a "golden age" for the Church. Or to say it differently, the only golden age for the Church is now, in the unity of faith and order, which the Pope embodies as a kind of gigantic scandalous walking sacramental. The following thesis is incautiously worded but basically true: The only thing that matters in the Church is the epiclesis. The Church only exists, really, substantially, in the precincts of that moment. In every age the challenge is not ingenuity––indeed, heretics are usually the greatest boons for ecclesial creativity––but rather is obedience to the incarnate order that makes faith, hope, and love meaningful for all humans.