T 1670B Nāgasena Bhikṣu Sūtra

Part 2: Dialogues

2.34. The Sustained Thought

The king asked Nāgasena again, “What is reflection?” Nāgasena replied, “When the mind gives rise to thought, then there is a reflection.”

“How does reflection give rise to investigation?”

“It is like a copper vessel or bronze plate when beaten by a man, it makes a sound. When it is raised up, it still gives out lingering sound. The man is also the same, when the mind is active, then thought arises. When the plate is beaten, it is called reflection, when it gives sound, it is called investigation.”

“Excellent, Nāgasena.”