Doubt and faith
Doubt and faith go together, an inner tension that allows choice and seeking.
I have found that those who are sure of themselves, without doubt, come across as angry, myopic and fearful of other ways of thought. Eric Hoffa said that the sign of a fanatic is one who can't abide anyone believing or thinking differently than them. A fanatical Christian for instance, if he or she loses their faith will become a fanatical atheist, and vise-verse of course.
How do you deal with doubt? I am speaking to both atheist and believers. Even though I am not an atheist, I do believe that 'truth' is something we all seek at ever deeper levels. To stop seeking truth, is to I believe becoming a fanatic of some sort. Both fundamentalism and atheism are for me too simplistic an answer to the complexity and mystery of our existence. The big questions can't be answered by science, though without science we would be worse off than we are now. I believe that both science and religion as well as philosophy are equally important for mankind.