It is well known that Nagarjuna, who lived in the late 2nd century, engaged in debates that were called destructive (vitandâ). Such a tactic is close to skepticism. In other words, Nagarjuna refuted his opponent's thesis without having one of his own. But I would argue that, in fact, Nagarjuna did have a thesis—an unusual thesis. It was the ultimate truth (paramartha-satya) which, being unconditioned, could not be debated since all debates were by nature conditioned, revolving around conventional truth (samvriti-satya). This all comes from Nagarjuna’s two truth theory which, I hasten to add, is not without some problems.
To understand Nagarjuna's two truths we first have to consider the distinction between them. Conventional truth is about non-definitive, verbal and conceptual teachings, which include debates. Hopefully this will help us to ultimate truth which can't be verbalized or conceptualized. But there are no guarantees of success.
This brings us to the real problem with Nagarjuna's two truths. How do we bridge them? How does one go from conceptual, non-definitive verbal and conceptual teachings to the big enchilada of ultimate truth or paramartha-satya? Even to explain the bridging process falls under the heading of conceptual. To be honest, there is a broad ugly ditch between the Buddha's conventional teachings, which are supposed to lead us to realizing, personally, paramartha-satya, and the direct realization of ultimate truth, itself.
Nagarjuna must have realized that there is no actual way to bridge the gap anymore than one can go from waves to water since there are really no waves at all when compared with the element of water. Conventional truth is but a configuration of ultimate truth like a vase which is made of clay. Conventional truth points in the general direction of where we must spiritually look, but the direction of our looking is not paramartha-satya. We still have to go there on our own, transcending all appearances.