I have a strange take on enlightenment as defined in Buddhism, which is that it is a trick you play on yourself. Someone searches for enlightenment and tries to attain it with everything they have so they become totally self-invested in the personal project. Then one day they realize that enlightenment which is non-conceptual non-experiential does not exist, per se, and that is why it is empty and nondual. But at that point their self which is invested so heavily in the project of attaining enlightenment actually collapses or sinks like a ship on the ocean. And that deconstruction of the invested self, is actually enlightenment.
And this is why there is so much paradoxical talk about enlightenment, as when people say you are already enlightened but just don’t know it. It is because once you are enlightened you realize that it was a false goal in the first place but that false goal had a practical psychological effect of deconstructing the self that was invested in enlightenment. So it is not true that just anyone is enlightened if they have not had the experience of the self-deconstructing. But this experience is itself empty, because it is the realization of the fact that there is no enlightenment per se. But this fact that enlightenment does not exist as something different from consciousness is precisely the bridge to the nondual of emptiness because it says ultimately that no goal exists, and everything in consciousness is empty like the goal of enlightenment, and thus enlightenment in the Buddhist sense is just this realization that just like enlightenment everything in consciousness is empty.
In Hua Yen Buddhism of Fa Tsang emptiness is identified with interpenetration. And it is in this identity that we see that what I have just said must be true, which is that everything is already interpenetrated, and enlightenment as the realization of the non-existence of enlightenment is just the realization that everything is already interpenetrated. However, you can only know that first hand if the self is deconstructed. At that pont one gets a glimpse of the interpenetration that comes with the emptiness of all things. All barriers between things are illusory, and that is because there was a big bang and everything is entangled from its origin in that singularity bursting out into existence. In the primordial singularity there were not differences between things. So existence is a single fabric of which we all are part, and it is only possible to see that if the self self-destructs, and the way we get it to do that is to invest everything in an false goal and then realize it is false.
This makes Buddhist enlightenment nihilistic. Nihilism is when you realize that to things that seem to be different are really the same like Form and emptiness according to the Heart Sutra. But it is a positive use of the transformative power of nihlism, it is almost as if it were using nihilism against itself to provide a transformative experience. If you have not had this transformative experience then you are not enlightened per se. But because the transformative experience is going to take you back to the state where you were before it from a new perspective of realizing that enlightenment is the same as mundane consciousness, then after you have that experience you know that there is no difference where you thought there was one previously between enlightenment and non-enlightenment. But before you go through that nihilistic realization as an experience you cannot really see that this is really the case because you have not really understood that enlightenment does not exist.
This is why the critique of Manjushrimitra who was one of the founders of DzogChen is so profound, because he points out exactly this self-deception that leads to enlightenment, and then leads back to a state which is prior to enlightenment and non-enlightenment, which can be seen as identical with mundane consciousness from a certain perspective. That is the perspective where one realizes that enlightenment as something that does not exist as different from normal consciousness. Taking this round trip is effective for changing ones perspective on the nature of things, i.e. the realization that they are empty, but if you do not take that trip and have the experience of emptiness then you are not enlightened and you are actually still caught up in nihilistic illusions and delusion. The fact that it is nihilistic because it is using nihilism to transform experience is interesting because it is precisely this use that produces the experience of emptiness which is nondual and allows one to make non-nihilistic distinctions. Since the Indo-european worldview inherently produces nihilism as an unintended consequence of having Being, this is a way to return those immersed in the Indo-european worldview to an understanding of Existence as empty. In this way, Buddhism is tied into the structure of the Western worldivew in an intrinsic way and it transforms it by using the nihilism that it generates against it.
From all this we see that you achieve enlightenment by confronting the basic nature of the western worldview and yourself, which is the unbridled production of nihilism. The goal is to make non-nihilistic distinctions. You can only do that if you reach a non-existent “headland above the world” as Nietzsche would say by which you understand intrinsically nonduality. There is no headland above the world, but if we project it and then put everything into getting there, then by realizing that it does not exist, it transforms us by showing us the alternative of nonduality that is beyond all the permutations of what ever dichotomies and logical categories that we can use to describe our experience. Buddhism probably gives us the deepest possible insight into our worldview that is available which is also at the same time an insight into ourselves.
rDzogChen of Manjushimitra and Mipham calls the bluf of Buddhism and connects it back to the Void of Taoism (Bon), and thus serves as a bridge from the nondual of emptiness back to the deeper unstriated nondual of the Void in Taoism.