Don't Know Mind

We live in a culture where we are told we "need to know" this or that. Or, we are told we should Know this or that.  Others are busy telling us what they know.  However, what is it that we should know? Korean Zen Master Ko Bong teaches: "if you attain don't know, that is your original master". (emphasis added). Our greatest teacher is what we don't know---not what we need, should, or do know. In the end, what do we really know?