Why Does the Tathāgatagarbha Not Pervade Empty Space?

Question: Why is it said that the tathāgatagarbha encompasses everything and pervades everything, yet it is also said that the tathāgatagarbha does not pervade empty space?

Answer: The word "pervade" has different meanings in different contexts. "Not pervading empty space" means not filling empty space. The tathāgatagarbha is not material form (rūpa); only things that are material form can fill empty space. What is not material cannot fill empty space. For example, dust can pervade empty space because it is matter and has physical form, whereas the tathāgatagarbha has no physical form and therefore cannot pervade empty space.

However, the tathāgatagarbha does pervade all dharmas. All dharmas are born of and sustained by the tathāgatagarbha, so of course the functions and operations of the tathāgatagarbha are present in all dharmas. This "pervade" means existing and functioning in a formless and markless way. Empty space is also a dharma, and the tathāgatagarbha pervades it as well, because empty space is born of and manifests in reliance upon the tathāgatagarbha.

But in any place within empty space there is no tathāgatagarbha. Sand and soil can exist in empty space, and air can exist in empty space, pervading it. The tathāgatagarbha, unlike these things, does not fill empty space. The tathāgatagarbha is not matter—how could it fill empty space?