Acharya Prashant explains the Zen concept of 'Mu' through the dialogue between a monk and Joshua regarding whether a dog has Buddha nature. He clarifies that 'Mu' signifies nothingness, suggesting that as long as one identifies with a specific form, such as a dog or a person, they cannot realize Buddha nature. Buddha nature is the vast emptiness that remains when individual identity and person-hood are completely lost. The speaker emphasizes that the dog and the Buddha are alike only in their nothingness; the dog is Buddha only when it has lost its 'dog-hood'. He further discusses how the question of having Buddha nature acts as a barrier to realizing it. Answering 'yes' is improper because it implies that the current ego-driven self possesses divinity, while answering 'no' is incorrect because it suggests something other than the ultimate truth exists. Acharya Prashant describes 'Mu' as a spiritual stretching of language that transcends the duality of yes and no. He notes that claiming 'I am Brahman' can be arrogant, while denying it is blindness. Therefore, 'Mu' is the only befitting response to real questions, as it avoids the traps of separation and identification created by Maya.