The physical body is compared to a reed that grows in the water. The reed appears to be substantial but is actually completely hollow. Likewise, the body appears to be substantial, something important, but really it has no essence. Mind itself is like the empty sky, without attributes of center or edge or colour or shape. To realise the nature of mind, one has to ultimately let go, just completely let go of all striving, of all creative mental activity. Just abandon all of these things which involve dichotomies. Mind is not subject to specifications like "it is this or it is that or it is the other thing". As long as we try to specify what mind is, we will always be lost and will never find its essential nature.

-- His Holiness Kyabgon Chetsang Rinpoche