20:17 Mu is much more interesting than he states. First it is humorous as Mu can be a dog's bark. "無" (pronounced "wú" in Mandarin and "mu" in Japanese). Then as he says the idea should be we all have buddha-nature - but the rebuke is NO! in Japanese(also MU) or Not (also emptiness) so the lesson is far more simple and profound. Mu is bark, it is not, and no - (you do not comprehend), and also finally Emptiness - which is shunyata - closer to a potentiality. What may be...