(1) According to Rob Burbea in Seeing That Frees, "both the neither-one-nor-many reasoning and the sevenfold reasoning are among the practices capable of revealing the emptiness of matter even at the most basic levels."
Regarding the neither-one-nor-many practice, he goes on to say: "Even if we imagine down to the level of subatomic particles, these will necessarily have parts facing in different directions, or interacting with other particles in this or that direction. Anything that occupies space must have parts.
Postulating the existence of a partless particle that would be truly singular will not work. It would be impossible to arrange or amass such particles in order to form any thing from them. Having no differentiable sides, other particles could not be arranged either side of it. Such a particle would not be able to bond or interact with other particles in any direction. All the surrounding particles would contact the central particle at the same point, and all effectively occupy the same space. Nothing with any extension could ever come to be."
When I imagine a partless particle, I simply think of a sphere. I can't see how the reasons he states refute that possibility. He seems to think that a partless particle could not possess mass, or would just be an infinitely small point. Why could it not just be a sphere that can't be divided any further?
(2) Two of the quotations he uses:
"The element of earth has no nature of its own." (Prajnaparamita Sutra)
"Matter itself is void. Voidness does not result from the destruction of matter, but the nature of matter is itself voidness." (Vimalkirtinirdesa Sutra)
What are the other "practices capable of revealing the emptiness of matter even at the most basic levels?" Specifically this belief in the inherent existence of the "element of earth", i.e. sub-atomic particles.