Confusion about delusion

How do you know if you are an undeluded seeker of truth? I imagine most people believe they seek the truth. Does any one think they are deluded? This question occurred to me (an atheist) as I was chatting with a fundamentalist about the basic epistemological underpinnings of his belief. We both claim to seek the truth but at least one of us is gravely in error and possibly both. But certainly not neither.

So if you truly value truth over other goods such as happiness and comfort, how do you go about seeking truth unfettered by preconceived notions and rationalizations posing as deep thinking? Even if you came up with a list of features of that truth seeking must exhibit, how would you know those were valid features?

It seems fairly straight forward to identify non-sensical thinking in others, is it really so hard to detect in yourself? At least one major stumbling block is that the less you know about something the worse your ability to gauge your expertise in that area.

So my first rule of undeluded truth seeking:

Learning about an issue you want to be undeluded about can't have a termination point; you must continue to revisit and explore. Learn both sides to the same depth even if you find the opposing view repugnant; at least understand how the opponent pieces together the facts on his side. If you don't take the time to really understand the othersides' arguments then you may be fighting a strawman w/o even knowing it. You must be as honest as possible about what you really know as opposed to what you merely suppose to be the case.

For instance, it's easy for atheists to believe that all fundamentalists are just ignorant and/or dumb. While I'm sure there are many who fit that description, there are plenty who are well educated and thoughtful who have struggled with those big issues that you think are killer questions. I can just about guarantee that any question you think you could ask a fundamentalist that would expose them as intellectually inept, has already been debated for 1000+ years in one form or another. You may not agree with the answer or the methods used to get there, but more than likely they are not ignorant of these questions.