There is an episode of "The West Wing" about faith titled, "Belief in Things not Seen." One definition of faith from Merriam-Webster is, "firm belief in something for which there is no proof." I like thinking about faith in this way. I believe in God (I wouldn't have capitalized the G otherwise). That being said, my concept of God is probably not the same as yours, and much to my Rabbi's chagrin, not the same as his. It is mine. I own it. I chose it. There is no empirical proof, so I would not try to convince you of the rightness of my position. You are welcome to choose to agree with me, and I won't try to sell you on my idea.
One thing that is very important to understand about faith, though, is that things believed do not require evidence that they are real. There is about as much evidence to support the Easter Bunny and Santa Claus as there is God. I am okay with that. The problem is that people use belief in other areas.
In high school, I was very good at math. At one point we studied proofs. There were ideas put forth and we had to either prove or disprove them. The truth of many of these ideas is now settled. This is what science does. Let's look at the facts that we have and prove or disprove an idea. When you are acting on faith alone, you give yourself permission to dismiss evidence.
For me, the clearest example of this was the Iraq War. Days before the invasion, Vice President Cheney was on Meet The Press. He repeated the oft mentioned assertion that we would be greeted as liberators. When he was asked what would happen if we weren't, his response was simply, "We believe we will be." No evidence was necessary because it was a belief.
The Republican Party talks about faith a lot. Often, it is in terms of religious faith, but it spills out to other areas. They say they don't believe global warming is real. They don't believe in evolution (It's only a theory, after all). This allows them to ignore the fact that much of what Darwin wrote about has actually been proven in laboratories around the world.
This is the true problem with faith. Instead of cognitive dissonance allowing the mind to expand, contradictory facts are ignored, treated as if they simply do not exist. Faith allows people to untether statements from facts and actions (I.e, from reality). For example, it allows Republicans to say that President Obama doesn’t love America, they believe, in the same manner as Governor Romney. Saying, I believe, eliminates the need to back up the statement. Let me give you another example.
There used to be a place near where I worked called Fuddrucker’s. It was essentially an upscale burger franchise. They had the regular hamburgers, and bison burgers, and ostrich burgers. The big draw for me was the fixings counter; thick sliced beefsteak tomatoes, pico de gallo, pickles, onions, jalapeno cheese to name a few items. Anyway, a right-wing friend of mine used to make fun of me for going to Fuddrucker’s. He dismissedly would ask why I liked the place.
I took him there. He loved it. He would rave about the taco salad he ordered. A week later it was like his visit never happened. The next time I mentioned going to Fuddrucker’s he was just as dismissive as he had been before. He believed the place was not good. Since his actual experience (on more than one occasion), conflicted with his belief, the experience got expunged from his brain.
Paul Krugman does an excellent job of pointing out why this is dangerous in his column “Grand Old Planet”. However, it goes farther than that, because, as Stephen Colbert observed, “Reality has a liberal bias.” Bobby Jindal is being praised for calling Governor Romney on the carpet for his “Gifts” comments in the wake of his electoral loss. The problem is that he said, “We need to continue to show how our policies help every voter out there achieve the American Dream,” as if their policies actually do that. As Krugman points out, the Congressional Research Service dispels that notion. If only the Right could believe in the fact.