Does Pietism Ultimately Lead to Doctrinal Apathy?

I just read a great post over at Brothers of John the Steadfast that deals with the difference between pietism and confessionalism.  This also shed some light on something I have been pondering for some time: why is doctrine something about which Christians in general these days seem to care so little?  The answer, according to Klemet Preus, is pietism, which runs rampant in America these days.  I admit that I had not really made this connection, but it makes sense.  Here is something that Pr. Preus quotes in his article:

When
religion was conceived as primarily “in the heart,” “strict
denominational lines were blurred” in deference to “common religious
patterns” as pietism “directed mainstream American Protestantism…away
from the formal and corporate beliefs and practices of the church
toward the informal settings and personal affairs of believers." The result was the increasingly “small role the institutional church plays in the religious life of the pietist.” The clash between the established churches and pietism was inevitable
as “traditionalist Protestants resisted” pietism because it “undermined
the importance of creedal subscription, ordination and liturgical
order…[and] spoke a different idiom, one that was individualistic,
experiential and perfectionistic, as opposed to the corporate,
doctrinal and liturgical idiom of historic Protestantism.” To
Confessional Protestants, the Pietists blurred all denominational
distinctives expecting a “generic” type of Christianity of “sincerity,
zeal, and moral life.”

This also ties in with the idea often expressed by Rod Rosenbladt, Michael Horton and the WHI gang that pietism ultimately leads to liberalism – after all, if the main focus of Christianity is what happens in your heart, it's not too much of a stretch to come to the conclusion that all that matters is what happens in your heart, regardless of what is objectively true or factual.  Thus you have "X may be true for you, but Y is true for me" or "Christ didn't bodily rise from the dead, but He's alive in my heart."

This makes me wonder what relationship pietism has to postmodernism and the Emergents.  But that's a topic for another post …