Faith and reason coexist primarily as idealistic concepts that we misunderstand and misuse.
People who uphold reason as their motivator usually fail to see where their own unjustified assumptions lie. We've all got them, deep down (or not so deep).
People who are proud of their faith fail to acknowledge the real reasons they feel so comfortable taking actions without sufficient concrete evidence. (Childhood training, feeling of excitement, joy, or group acceptance...)
I see faith and reason as labels at each end of a scale.