Now I will expand on this explanation. The name "Diamond Sutra of the Perfection of Wisdom" points to how it shatters all phenomena into emptiness and dissolves the very concept of "one" into ultimate reality. It is extremely hard and sharp, hence the name "diamond." Wisdom is the ability to decide and discern; insight is clear understanding. Though the myriad appearances are vast, both objects and self are without fixed form. All conditioned activity ceases here, and in stillness, awareness naturally shines. That is why it is called the Perfection of Wisdom, or Prajna.

In Sanskrit, it is called *vajra* or sometimes *cakra*. Translated into Chinese as "diamond," it means a sharp metal tool, also known as a "breaker." The *Mahāparinirvāṇa Sūtra* says, "The Buddha told Kāśyapa, 'Your decisiveness now is like a sharp knife.'" It also says, "When the fire at the end of an era blazes, all things are consumed, but the sharpest, hardest substance remains as the diamond ground." And it adds, "The relics of the ancient Buddhas transform into diamond wish-fulfilling jewels."

Here, we take the simile of hardness and sharpness in a comprehensive sense. The older interpretation says the substance is hard and the function is sharp: the substance being hard means it cannot be invaded by delusions; the function being sharp means it can destroy all things. Now, someone may ask: "If the substance is only hard and not sharp, and the function is only sharp and not hard, then it could also be said that the substance has no function and the function has no substance. This would mean it is neither hard nor sharp. So what kind of hard and sharp is this? As the *Śataśāstra* says, 'The eye does not know, the mind does not see. If individually they cannot do it, how can they together?'"

Now I will use the *Madhyamakaśāstra* to answer this question, and then there will be no difficulty. What we call "hard and sharp" is actually neither hard nor sharp; we only speak of "hard and sharp" as a conventional expression. It is like saying "suffering" is defined by its absence, "impermanence" is defined by permanence, "emptiness" is defined by non-emptiness. This is all the same kind of logic, and it naturally avoids such objections. Prajna is like a mass of fire—you cannot touch it from any of the four sides. How can you dogmatically define it in terms of substance and function?

Substance and function arise interdependently; they are neither one nor different. If the substance is hard, the function is also hard; if the substance is sharp, the function is also sharp. Since they are not identical, we use terms to distinguish them. If we say the substance is hard, we also say the function is sharp—this is just one side of conventional explanation. Apart from the function, there is no substance; apart from the substance, there is no function. The function is itself stillness; stillness is itself function. There is no separate, functionless substance that governs the function, nor is there a separate, substanceless function that governs the substance. They are neither one nor different. Yet, due to interdependence, we can sometimes speak of them as one or as different. To counter the view of oneness, we speak of difference; to counter the view of difference, we speak of oneness. We provisionally speak of oneness or difference to help living beings realize that true nature is neither one nor different. This interdependence that is neither one nor different is what cuts off the deluded views of permanence and annihilation. When such speculative views cannot penetrate, that is hardness; when it can cut off those views of permanence and annihilation, that is sharpness.