"The centerpiece of his Madhyamaka or 'middle way' philosophy is the thesis that everything is empty. This thesis has a profound consequence. Ultimate truths are those about ultimate reality. But since everything is empty, there is no ultimate reality. There are, therefore, no ultimate truths. We can get at the same conclusion another way. To express anything in language is to express truth that depends on language, and so this cannot be an expression of the way things are ultimately. All truths, then, are merely conventional. [...] The views that one must relinquish are views about the ultimate nature of reality. And there is no such thing as the ultimate nature of reality. That is what it is for all phenomena to be empty. [...] There are, therefore, ultimate truths. Indeed, that there is no ultimate reality is itself a truth about ultimate reality and is therefore an ultimate truth!" (10-11)
Of course this sounds like a contradiction to our formal logic. But per previous posts they use paraconsistent logic, or vision-logic in my interpretation. Or as they call it in the article, the "transconsistent" (18). They note that Nag goes beyond the 'limit of expressibility' paradox akin to Wittgenstein, Derrida and Heidegger (and similar to Thakchoe in this series of posts) but adds the 'ontological paradox.'
"If Nagarjuna is correct in his critique of essence, and if it thus turns out that all things lack fundamental natures, it turns out that they all have the same nature, that is, emptiness, and hence both have and lack that very nature. This is a direct consequence of the purely negative character of the property of emptiness, a property Nagarjuna first fully characterizes, and the centrality of which to philosophy he first demonstrates. Most dramatically, Nagarjuna demonstrates that the emptiness of emptiness permits the 'collapse' of the distinction between the two truths, revealing the empty to be simply the everyday, and so saves his ontology from a simple-minded dualism. Nagarjuna demonstrates that the profound-limit contradiction he discovers sits harmlessly at the heart of all things. In traversing the limits of the conventional world, there is a twist, like that in a Mobius strip, and we find ourselves to have returned to it, now fully aware of the contradiction on which it rests" (19).
We see from above the sort of both/and/neither/nor para/transconsistent vision-logic that requires a 'fold' or twist, as in a Mobius strip. The very fold I've been talking about from the beginning of the thread, but translating it into other terms/paradigms, including kennilingus. And all of which changes the very nature of what is called so-called 2nd-tier or postmetaphysical thinking.
Also see Priest's article "The logic of the catuskoti."