The first meaning of "doubt" given in the Oxford English Dictionary is "The (subjective) state of uncertainty with regard to the truth or reality of anything; undecidedness of belief or opinion." This is no lesser state, no step on the way to faith--it is a dynamic state of challenge, or continual questioning. It can keep us intellectually alive and vigorous.
Yet we hide it, many now saying that we on the left should emphasize our values and elide discussions of our doubts.
To me, however, doubt is a core value not only of the left, but of the intellectual forces that created the United States and that, yes, have been the force behind all progress in Western civilization for 2,500 years.
There's much to be said for serendipity. I've been thinking about doubt since responding to a dKos diary last night. The diarist is one I respect most, but he feels quite strongly that doubt should not be accented in discussions by members of the left with those leaning towards rightist fundamentalism. To me, that's hiding our light. So, this morning, as I was driving, I was pleasantly surprised by a show that came on to NPR, Speaking of Faith; Jennifer Michael Hecht was featured. She is the author of Doubt: A History, a book that celebrates the long history and success of doubt. She speaks of doubt as a "magical quality of human experience." I agree completely and will celebrate, not hide, my doubts.
Let's take back enthusiasm for that great value, doubt.