One of the greatest things that I ever learned from an atheist was that there was value in questioning authority, in doubting. Doubt is not always a bad thing. Doubt is not the opposite of faith. In fact, it is by doubting that all of us have come to discard certain beliefs, while embracing others. In a way, we can’t have faith without doubting something else first.
There was a time in my life when I doubted that the universe was older than ten thousand years old. In later years, after applying critical thinking I came to realize that the universe was in fact billions of years old. So then the true value that should be embraced is critical thinking, and not doubt itself. Doubt is only good when it is based on sound critical thinking. Doubt simply for the sake of being cynical is not good doubt.
If doubt is not the opposite of faith than what is? The true opposite of faith is really faithlessness or unfaithfulness. A person who is full of faith lives in accordance with the beliefs they have come to hold, despite their changing moods and the everyday struggles of trying to live those beliefs out. Certain beliefs are held by the majority of theists and atheists alike, such as the belief that it is wrong to cheat on one’s spouse, of that it is wrong to neglect one’s children. A person who continues to trust in their beliefs to the degree that they live them out can in this sense be called faithful, as opposed to unfaithful.
“Faithless is he that says farewell when the road darkens” ― Gimli (JRR Tolkien) The Fellowship of the Ring