If you've seen The Martian--or even the trailer for it--you've probably been struck by a line spoken towards the end of the movie:
I guarantee you that at some point, everything is going to go south on you. And you're going to say this is it -- this is how I end.
Now you can either accept that -- or you can get to work.
In saying this, Mark Watney (the main character) gives voice to a kind of robust and emphatic faith. It is a faith that exists in spite of incredibly intense doubts; and it exists not by erasing those doubts, or by proving them wrong, or by banishing them from his mind.
It exists simply because he makes a choice. He makes a choice to value life, and to fight for it with all of his being. He makes a choice to face incredible odds not simply with calculation, but with courage. He makes a choice not to give in to despair.
In making that choice, he is not rejecting rationality. On the contrary, his rationality and his scientific mind are the things that keep him alive, that keep the story moving forward. He has not rejected science and rationality -- he has put them into the service of his will to live.
Someone else might have told him that his odds of dying were a thousand to one. But he chooses to aim for that one, that fraction of a percentage point, even if the odds of hitting it seem hopeless. In doing that, he taps into something that others might have easily missed: the odds can never fully account for our actions. The odds exist, but we can skew how they roll. We can weight the die.
This is his faith: to choose life, and to keep choosing life no matter what. Regardless of how he feels, regardless of what he thinks, regardless of what is going on. He chooses to live. He chooses to keep working. He chooses to struggle.
For too long, American Christians have been obsessed with a simplistic and unbiblical idea of faith. In this view, faith is just a matter of intellectually agreeing with certain statements. God exists, Jesus is his son, I'm going to heaven. By agreeing with these, the thinking goes, we become right with God and insure our eternal reward.
This view leads to two huge problems.
First, it breeds apathy and disinterest, as whole groups of people abandon any efforts to do good in the world. They've got their faith, they think, so why worry about anything else?
Second, it leads thinking Christians into intellectual crises. If faith is a matter of intellectually agreeing with certain statements, and if I sometimes have doubts about some of those statements, then I must not have enough faith. Perhaps I am even unfit to be a Christian.
This thought process has led many smart young people straight out of Christianity. They couldn't avoid certain doubts, and since "not doubting" was apparently the most important thing, they decided to give it up altogether. More to the point, they figured they already had.
Ironically, this kind of "intellectualizing" approach to faith favors those who have little interest in the intellectual. It's easier not to doubt something if you never think about it.
Contrast this with the biblical concept of faith. Consider Abraham.
Abraham was promised that he would be the founder of a great civilization. The book of Romans tells us that he had faith, and this faith was credited to him as righteousness. But this faith was not simply a belief--it was a choice to trust this promise, to follow it out into the wilderness. And this faith wasn't free from doubts--Abraham experienced tremendous doubts along the way, and despite a lot of waffling, ultimately stuck with the plan.
This example of faith is the biblical example of faith, and it is an example of someone who made a choice, and kept making that choice.
For the early Christians, their faith wasn't about a list of intellectual points they all agreed on. Their faith was in the promise that through Jesus, God was recreating the world. Their faith meant a choice, every day, to live as if that promise made sense, as if the real power in the world was seen in compassion rather than in violence.
Someone on the outside could have told them that the odds of them winning their showdown with the Roman Empire were 1000-to-1 against them. But they chose to aim for that one--because the thing about odds is, they can never fully account for our actions.