Oh definitely. Some doctors are physically incapable of uttering the words “I/We don’t know.” I know a few doctors, and have asked a couple of them about this. In private, they’re very frank about the limits of modern medicine. But in front of patients, they’re afraid any sign of uncertainty will lead to patients concluding that some other quackery is just as good as actual medicine. I can definitely understand their perspective, but it does sometimes make them come across as arrogant know-it-alls.