"Life is such a mystery, no one can understand it, and one who claims that he understands it is simply ignorant.
He is not aware of what he is saying, of what nonsense he is talking. If you are wise, this will be the first realization: life cannot be understood.
Understanding is impossible. Only this much can be understood -- that understanding is impossible.
That is what this beautiful Zen anecdote says.
The master says, " I don't understand it myself." If you go and ask the enlightened ones this will be their answer. But if you go and ask the unenlightened ones they will give you many answers, they will propose many doctrines; they will try to solve the mystery which cannot be solved.
It is not a riddle. A riddle can be solved, a mystery is unsolvable by its very nature- there is no way to solve it.
Socrates said, "When I was young, I thought I knew much. When I became old, ripe in wisdom, I came to understand that I knew nothing."