Curiosity and Fear

How do I get past the assumption that "I know" and ask questions without an accusatory tone or feel like I am trying to prove myself, then balance that with seeking confirmation instead of just assuming?

See this article (based on the one below):

http://blogs.scientificamerican.com/unofficial-prognosis/2012/03/08/what-single-quality-predicts-a-good-doctor/

From this article:

. . . A second gem from Dr. Fitzgerald’s article is the message of how to actually go about exhibiting curiosity. Watching talks given by Nobel Prize winning scientists for inspiration, she noticed similarities in their ways of thinking. They all seemed to toss around ideas with no pretense of linear thought, no semblance of structure, and, perhaps most importantly – no pretense of competence . . .

. . . Dr. Fitzgerald hits upon something here that I have found particularly relevant in medical school. It is much more difficult to obtain knowledge, much less to propose something innovative, if you are preoccupied with proving yourself. In order to discover a good idea, you need the luxury to experiment with bad ones. To put forward incorrect hypotheses, explore false leads, and work through ideas without any particular end goal – or any guarantee you will uncover something at all . . .

. . . The pass/fail system during the first two years of many medical schools is a good first step in cultivating a non-pressured, curious environment. Especially at this early stage of training, we should be more concerned with gaining knowledge than with showing off that we’ve got it. Don’t understand something? Ask questions. I try not to let a fear of sounding “dumb” overwhelm an opportunity to learn . . .

Which is based on this PDF (also attached):

http://www.bumc.bu.edu/facdev-medicine/files/2010/09/Fitzgerald_AnnInternMed_1999_130_70_Curiosity.pdf

From original article:

. . . Listening to Nobel Laureates in medicine was revelatory. No linear thought here . . . The scientists seemed oblivious to intellectual constraints and unconcerned about being seen as naive or unknowledgeable . . .

. . . Curiosity without constraint, no preconceived image to emulate, no need for the facade of competence, opening inquiry into any area that stimulated their interest -- these qualities seemed common to them all . . .