All too Zen

The Abbot of a Zen monastery was stepping down and said his successor had to capture the spirit of zen in a message on the wall. Whoever could best express it would be the next Abbot. 
His best student wrote: 
The body is the bodhi tree, The mind a mirror bright. Be careful to keep the mirror clean, so dust may not alight.
The dishwasher in the kitchen, on seeing this wrote underneath :
The body is no bodhi tree, the mind no mirror bright. Since nothing is in any sense on what could dust alight?
The Abbott saw what the dishwasher wrote, and knew he was the chosen one. Yet since this would mean the dissolving of the monastery itself, he only reluctantly gave the dishwasher his begging bowl, the sign of transference of his authority, telling him to leave the monastery and not return.