The Buddha told a story to his monks:
“A young widower was devoted to his little son. But while he was away on business, the whole village was burned to the ground by bandits, who took away the little boy. When the father returned and found only ruins, he was brokenhearted. He thought that the charred remains of an infant was his own child, so he organized a cremation, collected the ashes, and carried them always in a special bag.
One day his real son managed to escape from the bandits and found his way back to his old home. His father had rebuilt the house. When he arrived, late one night, and knocked on the door, his father called, “Who is there?”
“It is I, your son. Please let me in.”
The father, still carrying the ashes and hopelessly sad, thought this must be some wretched boy making fun of him and he shouted, “Go away!”
The boy knocked and called again and again, but the father always made the same response, and at last the boy left, never to come back again.”
When he told this story, the Buddha added, “If you cling to an idea as the unalterable truth, then when the truth does come in person and knock at your door, you will not be able to open the door and accept it.”
– Udana Sutta
It’s very difficult to stop clinging to our ideas, believes, and even incipient amount of knowledge that we may have gained. This creates a wall around us and prevent us from being open to new learning and getting closer to knowledge.
One night while being conscious in the astral plane, someone there indicated to me that what I was holding as truth wasn’t really such absolute truth. My initial response was reaction to that person, I did recitation on them to see if I’m dealing with negative entity who is trying to mislead me, but that wasn’t the case. Much later I realized that I was trying to make the reality fit into a belief that I had. Even though that belief was supported with some basic knowledge, there is much more to it than what I thought.
There is often/always much more to reality than we are aware of, and if we close ourselves to what we firmly believe or “know” to be true, the doors to progress will remain shut. It takes a lot to stay open for the new, unhindered by the old. We may regard the old (ideas, believes, incipient knowledge) as pillars without which our temple would collapse and because of that we fear experiences that may expand our perception or even make us realize that what we regard as real and true is not really so. To progress it’s necessary to be able to question what we think we know, being prepared to expand it or let it go, and overcome the fear that keeps us in the ignorance of our comfort zone.