[A]nyone who seeks total Enlightenment should discard not only all conceptions of their own selfhood, of other selves, or of a universal self, but they should also discard all notions of the non-existence of such concepts.

When the Buddha explains these things using such concepts and ideas, people should remember the unreality of all such concepts and ideas. They should recall that in teaching spiritual truths the Buddha always uses these concepts and ideas in the way that a raft is used to cross a river. Once the river has been crossed over, the raft is of no more use, and should be discarded. These arbitrary concepts and ideas about spiritual things need to be explained to us as we seek to attain Enlightenment. However, ultimately these arbitrary conceptions can be discarded.

A Zen Master and his student were meditating in the woods when an ancient rotten tree suddenly came crashing down near them. The student remarked how ironic it would have been if the tree had fallen onto them as they were sitting there meditating.

"It would have been fortunate!" retorted the Master.

"Why?"

"If a tree falls in the forest and nobody is around to hear it, does it make a sound?"