On one occasion the Venerable Ānanda and the Venerable Udayī were dwelling at Kosambī in Ghosita’s Park. Then, in the evening, the Venerable Udayī emerged from seclusion and approached the Venerable Ānanda. He exchanged greetings with the Venerable Ānanda and, when they had concluded their greetings and cordial talk, he sat down to one side and said to him:
“Friend Ānanda, in many ways the nature of this body has been declared, disclosed, and revealed by the Blessed One thus: ‘For such a reason this body is nonself.’ Is it possible to explain the nature of this consciousness in a similar way—to teach, proclaim, establish, disclose, analyse, and elucidate it thus: ‘For such a reason this consciousness is nonself’?”
“It is possible, friend Udayī. Doesn’t eye-consciousness arise in dependence on the eye and forms?” sn.iv.167
“Yes, friend.”
“If the cause and condition for the arising of eye-consciousness would cease completely and totally without remainder, could eye-consciousness be discerned?”
“No, friend.”
“In this way, friend, this has been declared, disclosed, and revealed by the Blessed One thus: ‘For such a reason this consciousness is nonself.’
“Doesn’t ear-consciousness arise in dependence on the ear and sounds?… Doesn’t mind-consciousness arise in dependence on the mind and mental phenomena?”
“Yes, friend.”
“If the cause and condition for the arising of mind-consciousness would cease completely and totally without remainder, could mind-consciousness be discerned?”
“No, friend.”
“In this way too, friend, this has been declared, disclosed, and revealed by the Blessed One thus: ‘For such a reason this consciousness is nonself.’
“Suppose, friend, a man needing heartwood, seeking heartwood, wandering in search of heartwood, would take a sharp axe and enter a forest. There he would see the trunk of a large plantain tree, straight, fresh, without a fruit-bud core. sn.iv.168 He would cut it down at the root, cut off the crown, and unroll the coil. As he unrolls the coil, he would not find even softwood, let alone heartwood.
“So too, a bhikkhu does not recognize either a self or anything belonging to a self in these six bases for contact. Since he does not recognize anything thus, he does not cling to anything in the world. Not clinging, he is not agitated. Being unagitated, he personally attains Nibbāna. He understands: ‘Destroyed is birth, the holy life has been lived, what had to be done has been done, there is no more for this state of being.’”