This koan is discussed in Part 1 of Hau Hoo's "The Sound of the One Hand: 281 Zen Koans with Answers". In it, the answer of "negative", mu, is clarified as although all beings have potential Buddha-nature, beings who do not have the capacity to see it and develop it essentially do not have it. The purpose of this primary koan to a student is to free the mind from analytic thinking and into intuitive knowing. A student who understands the nature of his question would understand the importance of awareness of potential to begin developing it.