Most people don't know how to define faith. The faithless mock the concept as one simply believing something based on nothing whatsoever but we'd all agree that that isn't what faith is, or is it?
When I was a Christian I came to a place where I labelled myself a "Presuppositional Evidentialist". In other words, I was at odds with a Fideism. I didn't believe faith was believing without reason. It was inherently tied to it. My view of faith is this: Faith is the ladder that takes us from the known to the unknown. In other words, when you hear Christians give illustrations of faith they liken it to trusting the brakes in your car, a chair to support your weight, the sun to rise again in the morning and so on and so forth. The reason I have faith that my chair won't collapse under my weight is because of the evidence I already have. It's from this evidence that I can trust the chair, that I can have faith in it.
So my beliefs in Christianity were inherently tied to Evidentialism. The reason I came to the conclusion that Christianity is true and the reason I continued in that faith was based on the perceived evidence around me. I believed there was historical evidence in support of the Bible being the word of God and I believed there was scientific evidence in support of a Fundamentalist worldview in which the world was 6, 000 years old. So long as this evidence was maintained then so was my worldview.
I was also (interestingly enough) a presuppostionalist. What that means is I gloried in the fact that I used circular reasoning to defend my faith. Or, to put it a little more eloquently, I believed that we all have presuppositions and it is through those presuppositions that we understand our world. Here is the hitch though, without Biblical presuppositions you can never come to the "right" conclusion about things because you are understanding the world through a faulty looking glass. Only Biblically based presuppositions offer a crystal clear looking glass to understand the world and come to the "right conclusions". In other words, thinking there is no God, that evolution is real and all that is the only conclusion you can come to without Biblical presuppositions. You cannot believe the Bible is true through them until you change them.
My weakness I guess was that I held more strongly to evidentialism than I did to presuppositionalism. Once you kicked out the cane of "evidence" I was leaning on, that was pretty much it. This is why I think it's important to understand how someone understands what faith is. Once you've understood their definition than you understand how to knock them off their feet. If someone holds onto fideism than you can rest assured an evidence based approach won't work against them, at least not yet. With someone like that you must bring them to the conclusion that all faith is based on some evidence. Once they realize that you can slowly begin walking them through the cold hard fact that Christianity has no reliable evidence to base one's faith on.