It's not pleasant. It hurts. The ground goes wobbly. You may be reaching for sleeping pills or alcohol or a lover to get you from 2 to 4:30 a.m. each night.
But it's good because we want to be open to truth and what it means for us.
Just a few examples of those uncomfortable thoughts: Maybe there isn't actually a God? Maybe there is? Maybe there is only one version, or maybe a multitude? Maybe evil and suffering are far more prevalent and powerful than I ever knew? Maybe the ideals I held so dear and fought for make no sense in the real world? Maybe I've let ambition cannibalize my ability to love? Maybe I've just found what I want to live for, but it will demand that I leave so much behind?
Sometimes our beliefs about the world evolve slowly. Other times a lightning bolt tears a wound in the old to illuminate what is new.
Last year I wrote a book  while working on the response to the earthquake in Haiti . The subtitle is "searching for honest faith when your world is shaken." I was thinking about my own faith and the faith of friends in the wake of the staggering suffering of the moment and aftermath.
Of course, this horror reveals nothing new about our world. We know it from the tsunami or flood  or whatever comes next. But I wanted to ask if it revealed anything new about my faith. This tragedy was different for me because the enormous scale was also deeply personal from working in the country for eight years.
The world crashes around us all the time in different ways that can provoke a crisis of faith. Another example is the approximately 4,000 diagnoses of cancer each day.
But a crisis of faith can also come from positive experiences. We learn new things, science makes new discoveries, we have epiphanies and understand life or love or our spirits in new ways that make the old nonsensical.
Whatever causes a crisis of faith , there is often emotional, intellectual, spiritual turbulence along the way.
So this is, I guess, an ode to having crises of faith. I don't know if we should exactly invite them. Maybe. But at the least we should welcome them when they come and not chase them away. It's a chance to ask if we can receive something new and true , regardless of whether it's disturbing or liberating.
I'm not celebrating wishy-washiness. Quite the opposite. I'm arguing that we need to be committed to truth. And in the beautiful, tragic, complicated world that we live in, that necessarily means we'll have crises of faith along the way.
Let's follow them truthward.
Kent Annan is co-director of Haiti Partners (www.haitipartners.org ), which has set up an Earthquake Response Fund. He is the author of After Shock , which explores questions of faith, doubt, and searching, and he is also the author of Following Jesus Through the Eye of the Needle: Living Fully, Loving Dangerously , which is about living and working in Haiti.