According to some teachers, the most fundamental statement in Zen is "I don't know". For example, Zen Master Wu Kwang (Richard Shrobe) tells this tale:
Poep An came to a particular monastery and greeted Master Ji Jang, who was to become his final teacher. Ji Jang asked Peop An, "You're travelling all around China; what's the meaning of your pilgrimage?" Initially, Peop An felt stuck and momentarily all thinking stopped. Then he said, "don't know". Ji Jang responded, "Not knowing is most intimate". Sometimes you'll see this translated as: "Not knowing is closest to it." ...This one sentence, "don't know" or "Not knowing is most intimate", is very much at the heart of our practice.
This idea goes all the way back to the semi-mythical founder of Zen, Bodhidharma, and an interview he supposedly had with the Emperor of China. The Emperor, who had sponsored all sorts of temple-building and sutra-copying, was not pleased with this smart-assed barbarian telling him that this wasn't going to get him reborn in the Pure Land or whatever, and so challenged him by saying, "Who are you?" (I've always read the subtext of that as "Who are you to give me lip, monk?") Bodhidharma's amazing answer was, "I don't know."
Another way of expressing this idea comes from Zen Master Shunryu Suzuki: "In the beginner's mind there are many possibilities, but in the expert's there are few."
There's a Star Trek: The Next Generation episode where Data expresses a similar idea: "Captain, the most elementary and valuable statement in science, the beginning of wisdom, is I do not know. I do not know what that is, sir."
The beginning of wisdom is, "I don't know." What an amazing idea.
Have you ever tried to teach someone something, only to be told, "I know, I know!" I've been on both sides of that one! If I know, then I'm closed off to learning, but if I'm not attached to "knowing," the possibilities are endless.
Let's juxtapose that with a Twitter post from the man behind the recent massacre in Norway. Anders Behring Breivik, the lunatic who killed at least 92 people in what seems to be a politically motivated attack, recent posted this: "One person with a belief is equal to the force of 100,000 who have only interests."
If we didn't know the context, we might look at that and think it a positive statement about the value of strong belief and determination. But in order to go off and shoot scores of people, Breivik had to "know" that what he was doing was right.
Just a bit of "I don't know" could save a lot of lives.
Yeats's poem "The Second Coming" has the famous lines, "The best lack all conviction, while the worst / Are full of passionate intensity." While perhaps a situation where the best lack all conviction tilts too far, it will always be the case that the wise have doubts, while those who perpetrate violence lack them. You've got to be pretty damn sure of your ideas -- pretty damn attached to them -- to kill people over them.