This dialog strongly reminds me of Hui-Neng's first public appearance as the sixth Zen patriarch. This is how D.T. Suzuki recounts it:
"He saw some monks arguing on the fluttering pennant; one of them said, 'The pennant is an inanimate object and it is the wind that makes it flap.' Against this it was remarked by another monk that 'Both wind an peannant are inanimate things, and the flapping is an impossibility.' A third one protested, 'The flapping is due to a certain combination of cause and condition'; while a fourth one proposed a theory, saying, 'After all there is no flapping pennant, but it is the wind that is moving by itself.' The discussion grew quite animated when Hui-Neng interrupted with the remark, 'It is neither the wind nor the pennant but your own mind that flaps." This at once put an end to the heated argument."