re: "Are there any techniques you use to overcome such certainty?"

As you have discovered, beliefs tend to firm up the illusion of certainty. It almost doesn't matter what the belief is, its function seems to be the same: protecting fragile psyches from the more strident reality of uncertainty. People need their pet beliefs and dogmas to take the edge off realities too harsh for their current ego structures. In this way, beliefs serve the purpose of buffering us from more truth than we are ready and/or willing to live with.

The signals of ANNOYANCE and IIRRITATION betray the existence of our buffers, our fixed assumptionjs and beliefs. When something or someone really annoys you, it's probably going to be important.

As for techniques to overcome certainty, I suggest relaxing the "meaning reflex", ie., relaxing the tendency to project or assume meaning onto your perceptions. This technique helps cultivate "the second attention". The first attention is that awareness linked to the thinking mechanism, language and the automatic assignment of meaning to whatever is perceived. The second attention is that awareness linked to presence, energy and phenomena without assigning any meaning whatsoever. It expresses more of a pure seeing.

ideally, the two attentions are meant to work together however, the first attention has a clear monopoly of the human mind, at least in Western culture, and why so many of us are tyrannized by it. As we are tyrranized, so then do we tend to tyrannize lothers; we can't help it. It's a reflex; the meaning reflex. "My meaning is more meaningful than yours. Your meaning is bogus."

The need to "be sure" might also be a misgiuded attempt to meet a security need where no security is required. Meet your security needs more directly and free yourself of the need to be sure. Learn to permit more uncertainty.

"The border between the Real and the Unreal is not fixed, but just marks the last place where rival gangs of shamans fought each other to a standstill." -- Robert Anton Wilson

I had an overcoming belief growing up that the Southern Baptist Church had the whole truth and it made me nervous, and felt like I wasn't sure what was real or if I was a good person. It made me feel shameful and negative. As I grew up, and discovered Robert Anton Wilson, and yeah, well just sex in general, I began to think a little more for myself and eventually realized that some people's beliefs don't support who I am.

Oh, yeah, I've had dolphin dreams that seem real, like some telepathic communication was going on, but hey, that's just me.

Peace,
Ron

RE: Are there any techniques you use to overcome such certainty?

What is it that makes you believe that someone's beliefs need correcting? I'd guess it's some sense of superiority, because you believe your beliefs are more right than theirs... ?

Research and evidence have become buzzwords for the New Inquisition. Anything not done in a lab by some lettered dodo in a white jacket doesn't count for anything in the minds of a scientific materialist. I think that's a pretty limited way of looking at the wondrous whole of existence and its perplexities and complexities. But it's not my job to correct that error in their thinking. Hell, maybe they're right.