At Sāvatthī.
“What do you think, Rāhula?
Is perception of sights permanent or impermanent?”
“Impermanent, sir.” …
“… perception of sounds …
perception of smells …
perception of tastes …
perception of touches …
Is perception of ideas permanent or impermanent?”
“Impermanent, sir.” …
“Seeing this, a learned noble disciple grows disillusioned with the perception of sights, sounds, smells, tastes, touches, and ideas. …”