How much knowledge can a man acquire in a lifetime? If he could read every book written- an impossibility- his knowledge would still be limited. He would never know, for example, the pain of childbirth, what a caterpillar experiences when it metamorphoses or what a tree knows. Yet, man in his hubris (and it is usually men), asserts- with certainty- that there is no God or, conversely, to know the mind of God. It is the same condition and points to a lack of humility. Many are afflicted with this, but their ignorant certitudes find their audiences. They do not know how the engine in their car runs, but they can tell you how to better run the economy, the government, the world. They do not know how the mind of their 13 year old adolescent works, but they can explain 13 billion years of creation. That the universe is 13 billion years old, by the way, is just an estimate. We may be authors of ideas, concepts and beliefs, but we are not authors of Reality- although, we do, to an extent, author our own narratives (and miseries). Most of these thoughts, however, are not native, original or of our authorship- but borrowed and claimed as ours, which we then defend vigorously... sometimes to the death.
Suppose a man lives 125 years (surpassing the record) and applies himself to study, the cache of what he does not know will still be greater than what he does know. There are mysteries. However wise he may become, he will not reverse old age nor avert death. Then there are those experiences which transcend reason and intellect. The adept meditator will experience subtleties that cannot be articulated, explained, or replicated.
We are enjoined to approach each sit with a beginner's mind or the Don't-Know-Mind of an infant, expecting nothing, rejecting nothing. We keep the mind open and simply observe whatever unfolds moment by moment with curiosity. The deeper we go, the more we realize- experientially- how little the puny intellect truly knows. Humility flowers and the illusions begin to fall away; we cast off what we thought we knew.