"The killing fields of Cambodia come from the philosophical discussions of Paris."
Dallas Willard, The Divine Conspiracy (p.7)
Ideas matter. That's why theology matters. What we believe determines our actions.
Derek recently loaned me The Looming Tower: Al-Qaeda and the Road to 9/11 by Lawrence Wright. Wright traces militant Islam to the writings of Sayyid Qutb in the mid 20th century. What I find most shocking is that he spent quite a bit of time in the US. He was appalled at the lack of morals he observed, and especially the vain philosophies undergirding them. He in turn has influenced people from three generations (so far) to become terrorists. Theology really can change the world - for good or evil. There is no reason that Christian theologians cannot have the kind of (positive) impact on the world that Qutb's (negative) theology had.