The Buddha answers Rāhula’s request by teaching on the external sense objects in light of the three characteristics.At Sāvatthī. “What do you think, Rāhula? Are sights permanent or impermanent?” “Impermanent, sir.” … “… sounds … smells … tastes … touches … Are thoughts permanent or impermanent?” “Impermanent, sir.” … “Seeing this, a learned noble disciple grows disillusioned with sights, sounds, smells, tastes, touches, and thoughts. Being disillusioned, desire fades away. …”