Many, diagnosing the current ailments of the Church, contend that "We are where we are because of what we believe," meaning that the formal content of Church doctrines are cancerous, needing the radioactive treatment of postmodern, post-foundational philosophy (which is Brian McLaren's assertion). Now, certainly I have no serious argument that many doctrines (or at least their current formulations) are horribly deformed.
But posing the question in this manner assumes an unfortunate direct relation between knowing and doing, and therefore, reinforcing the priority of knowledge over practice (and speculation over affectation). This perspective overlooks the imaginative, or fantastic, aspect of agency, or the fact that how we relation our action to our belief is an creative act of interpretation. As Kevin VanHoozer says, "We have biblical doctrines, but secular imaginations."
So my point is that while some, or many doctrines, need revision (i.e. substitutionary atonement, premillenialism, etc.), our recent modernist method (or lack) of cultural engagement blinded the Church to syncretistic moves in relation to the Enlightenment, modernity, and even postmodernity. What the Church has generally failed to do is what Freudians would call "analysis", Marxists call "ideology critique", and the Church used to call "casting out idols."
So our ability to engage (and I don't even like that term anymore—"engage" sounds like Capt. Pichard on the Enterpise) the postmodern context, or liberal democracy, or global capitalism, doesn't just depend on recovering/articulating the Faith, but on articulating the idolatries/ideologies of the present age which insinuate themselves into the practices of the Church.
So the question is not how what we know affects what we do, but also how what we are doing doesn't accord with what we think we know. It is not what we believe, but how we believe.