"...Nagarjuna’s doctrine of the emptiness of emptiness involves many reasonings that interrelate in deep and comprehensive ways. To begin with, to be empty is to be dependently arisen and emptiness is no exception. Ultimate truth is fully dependent upon conventional phenomena to perceive their emptiness. And as entities are ultimately unfindable, this absence that is emptiness, cannot be non-empty and findable. This recognition uncovers the ultimate truth that emptiness is empty. But there is more to the argument.
It can also be deduced that if the emptiness of inherent existence is ultimately true, then emptiness must also be empty. If emptiness existed in the independent self-established sense, then emptiness would not be empty but inherently existent. And since everything is empty, that would make everything inherently existent too. So if phenomena were empty but emptiness was non-empty, the ultimate truth of the negation of inherent existence would itself be negated. Instead, the teaching that emptiness is empty is consistent with emptiness as an ultimate truth.
Nagarjuna’s reasoning extends into an eloquent somersault that completes the analysis. If emptiness is empty, as in an absence, then it can only conventionally exist. For there is nothing that can be identified about the emptiness of things, as in the example of elephantlessness. What is not conventionally designated does not exist in any positive sense, is not an object, hence its emptiness.
Therefore, to be empty is to only conventionally exist and likewise, to conventionally exist is the only way to be empty. Furthermore, as there are no true objects to know, conventional truth is also the only truth there is. This is the ultimate truth of emptiness and thus, a conventional truth. The doctrine of the emptiness of emptiness culminates in the insight that the two truths, the ultimate and conventional are ontologically the same, like two different sides of the same coin.
To recognize emptiness as conventional is to thoroughly refute inherent existence and to underscore the recognition that emptiness is the emptiness of conventional phenomena, nothing more substantive than that. This insight undermines a contradictory and dualistic reality where emptiness is totally real, while the conventional is totally unreal. Nagarjuna’s doctrine negates ultimate truth as an independent base from which to assert an objective, non-empty view. All views can only be conventionally true.
“Therefore it is said that whoever makes a philosophical view out of emptiness is indeed lost.” - Nagarjuna read it all