What is the color of your head from the standpoint of your eyes?
You feel that your head is black, or that it has not any color at all.
Outside you see your field of vision as an oval because your two eyes
act as the two centers of an ellipse. But what is beyond the field of
vision? What color is it where you can’t see? It is not black, and this
is an important point; there is no color at all beyond your field of
vision. This little mental exercise gives us an idea of what is meant by
the character hsuan. Although its dictionary definition is “dark, deep,
obscure,” it actually refers to this kind of no color that is the color
of your head – as far as your eyes are concerned. Perhaps we could say
that the invisibility of one’s head, in a certain sense the lack of a
head, is the secret of being alive. To be headless (to have no head in
just the sense I am talking about) is our way of talking about the
Chinese expression wu hsin, or “no mind.”