I've been blessed to study with many people who hold a variety of religious and non religious beliefs. I have a friend, Wilfredo, who converted to Islam; another friend, Andrew, who is devout to his Jewish heritage and religion. I've studied with Christians, Atheists, Agnostics, and a number of people who have lesser known religious beliefs. What became clear to me was the way faith and reason functioned inside these systems of belief.
Theism and Atheism are in contradiction with each other. Dialectically speaking, investing in one is divesting in the other. Faith and reason, at their simplest levels, are also thought to be contradictory notions; I believe this assumption, by some, is due to a breakdown in language. Faith is understood to be religious based and reason science based. What I've found is that faith can be derived from reason, and that a constitutive part of reason is faith.
At our instinctual level we seek to put order in the world around us. I'm a Christian metaphysian (small m) the claims I make about the nature of the world are in no way an attempt to make a universal philosophical system of thought. I understand the world through language, culture, and socioeconomic realities that I didn't choose. With all of that said, my perception of reality is limited by my stationary existence. I could be wrong in my interpretations and that could cause me to make false conclusions.
At their purest levels faith and reason supplement each other. Before many make pronouncements about their religious convictions they have reasoned with their interpretation of reality and made a leap of faith. This holds true for the nonbeliever as well. Scientific experimentation is based in a certain kind of faith: are my hypothesize grounded in enough hard evidence? Will the theoretical conclusions I've made coincide with reality?
The dumbing down of our culture has led to narrowly viewing science and religion. There's a faction of angry Theists who hold the view that they are morally superior to their Atheist contemporaries; while their equally angry Atheists contemporaries hold the view that they are intellectually superior to their theist contemporaries. Faith and reason are not opposites. They are vital components to any belief or set of beliefs about the world.