Like you wrote, the way we humans perceive what is true is like the way some blind men in a story felt and described an elephant. One described the elephant as a wall when he felt it's back or sides. The other called it a tree when he felt the legs, etc. That's how not seeing the whole picture of a situation, seeing it from our singular perspective, can make us think we are right, when, infact, we are not. That's why we should always be open to corrections, we should be open to adjusting our beliefs, because our perspective of things could be faulty.
Of course, the whole world could still believe that something is true when it's not. Like some outdated psychological or physiological beliefs that professionals in those fields, and even the masses of people outside the fields, believed to be true until evidences to the contrary emerged. It's a very slippery situation as I see it. The only solution is to put whatever beliefs we have to thorough testing before labelling them truths.