Faith is not "blind faith" or "wishful thinking"
In a previous comment by Nomad, he discussed the need for Christians to be careful in their use of language when discussing Christianity with skeptics. As part of his paragraph, he noted:
'Faith' always means 'blind faith' to the skeptic, and it never means simply 'belief,' or lesser still, 'trust.'
Nomad is absolutely right. In my view, this is one of the biggest problems in discussing Christianity not only with skeptics but within the Christian church itself. "Faith" is seen as closing your eyes and hoping for the best despite what the evidence may tell you. To those outside of the church (and to many within the church) if you have "faith" in something, it means that you will believe it regardless of the evidence.
You have probably seen this idea of "faith" played out in movies or in books. Perhaps the plot has the hero/heroine accused of a crime and it looks bad for him/her because the evidence appears overwhelmingly against them. Alternatively, the hero/heroine is asked to perform an impossible task which most anyone would recognize immediately as a suicide mission. But the hero/heroine's girlfriend/boyfriend says words to the effect of "I don't care what the evidence says, I have faith in you." Yup, that's the idea: faith comes in when the facts are against you.
But that is not the Biblical definition of faith. For that definition, go to Hebrews 11:1 where the Bible says: "Now faith is the assurance of things hoped for, the conviction of things not seen." Assurance is not a term of wishful thinking. The Greek word for "assurance" is "hupostasis" which has the following definition:
1) a setting or placing under
. . . a) thing put under, substructure, foundation
2) that which has foundation, is firm
. . . a) that which has actual existence
. . . . . . . 1) a substance, real being
. . . b) the substantial quality, nature, of a person or thing
. . . c) the steadfastness of mind, firmness, courage, resolution
. . . . . . . 1) confidence, firm trust, assurance
I believe that the second definition is the more consistent with the use. Note that it references that the foundation is firm. The meaning is inescapable: Biblical faith is based on a firm foundation. What is that firm foundation? A knowledge that Jesus actually, really, truly was God and was died and resurrected for the forgiveness of sins. Faith, in this sense, is not merely a blind, unreasoning hope.
So, how do we communicate this to the skeptic? Greg Koukl of Stand to Reason suggests that we use the word "trust" instead of "faith" when discussing Christianity with skeptics. In other words, when dealing with non-Christians, we should say (for example) that we trust that Jesus is God. That takes the "wishful thinking" aspect out of it, and allows us to explain why we trust that Jesus is God without the skeptic initially concluding that we are exercising "blind faith" against the evidence. I think he's right.