Continuing my series on the value of the liberal arts in college...
1. I've said before that philosophy logically stands at the heart of a liberal arts curriculum. This is because philosophy stands alongside every other discipline and clarifies what that discipline is really about and what is going on when you study that discipline. And, obviously, philosophy on a Christian campus will clarify all other disciplines from a Christian standpoint. 
2. Take critical thinking. Logic is one of the areas treated by philosophy, how to think clearly.
Logic is the bedrock of civilization, rational thinking. One of the things I find reassuring about logic is that it is timeless and absolute. It doesn't matter where you are from or when you live in history, logic does not change.
Learning about culture is also part of the liberal arts (history and sociology), and I strongly affirm its value as well. But civilization is toast if we yield to the notion that a European simply cannot understand an African or that a man simply cannot understand a woman. Logic cuts across location and particularity.
Different cultures may assume different propositions in their communication. They may have different rules for how one thought "causes" another. But the nature of cause and effect remains the same. A logician could "translate" conversation and culture into a clarified language of logic.
So "tribal" thinking is the enemy of civilization and philosophy undermines it at its very heart. Philosophy looks for truths that are bigger than us as individuals or groups. Philosophy says that the same truth applies to a white person as to a black person. Philosophy insists that each truth claim be considered on its own, no matter who suggested the truth.
This all sounds rather modernist, and it is to a large degree an impossible dream. But civilization steers by this dream of timeless, objective, universal truth. Postmodernism, if made the shining star, becomes the enemy of civilization.  Presuppositional epistemologies that overextend assumptions far beyond what is demonstrable are the enemies of civilization.  And a "party-spirit" such as voting only for one political party or only accepting information from one cable news channel is a threat to civilization.
Logic leads us to this conclusion, while giving each option its turn to speak and letting each student come to her own conclusion.
2. Philosophy lays bare our thought assumptions. It shows us ourselves. It shows us options we did not know to consider. In that sense it makes us "freer" persons, as the liberal arts are meant to. We now can freely choose option A among options A through E.
Before, we didn't know B, C, D, or E. We were an unthinking slave to option A. Now we may still choose option A, but we will now choose it freely rather than because our mommy always said that and we had never heard anything different.
A science major may think that he or she is completely objective. A science major may assume that empirical method is the only valid way to arrive at truth. Philosophy comes alongside and points out that science has a lot of assumptions. In walks Thomas Kuhn and makes it clear that science goes through trends and phases, that "normal science" resists paradigm shifts.
Even in religion, a person may assume that he or she is just reading the Bible and doing what it says. Philosophy comes alongside and points out that tens of thousands of other Bible readers think the same and yet disagree vastly with them. Philosophy points out that while the content of a person's theology may come largely from the Bible, the organization of that content comes from far more complex sources, including the interpretive traditions to which the Bible reader is heir.
3. Philosophy makes us humble. Despite the modernist bent of everything I've said so far, postmodernism does come along and warn us that even the philosopher is not outside reality looking on. I as a knower am part of what I am knowing. I cannot pull myself out of the world to make it an object. My interpretation of the world will always be unreflective and constructive to some extent.
Philosophy leads me to the conclusion that faith is intrinsic to all human knowing (except, perhaps, my sense that something exists). Philosophy suggests that the human elements to existence are more significant than the cognitive. Philosophy suggests that ideas are simply tools we use to help us make our way through the world.
But, then again, I am giving you my conclusions from philosophy, which no doubt relate strongly to my identity as a Christian. Nevertheless, conclusions like these, I believe, stand at the heart of a thriving civilization.
But philosophy will equip you and then let you decide. It is the ground zero foundation of the liberal arts... and potentially one of the most powerful weapons against barbarism.
See also this addendum.
 We are talking here about the cognitive dimensions of a curriculum. IMO, a Christian philosophy also suggests that these cognitive dimensions are not the most important human dimensions.
 Understand me. Insofar as postmodernism contributes to truths about the limitations of modernism, it is to be embraced. Underlying my scheme here is not contradiction but pragmatism, the only coherent philosophical option in the end. See my posts this fall as we read through Preludes to Pragmatism.
 Yes, I am targeting Reformed epistemology here as potentially hostile to civilization.