In Buddhism there is no acceptance of the reality of the physical world, which is the opposite of Taoism that reduces everything to nature. Thus for Buddhists all phenomena are in consciousness, which is a very Hindu prejudice and something that the Buddhists probably carried over from the Hindu tradition from which they were a heretical departure. If all there is is consciousness then enlightenment must be a modulation of consciousness, and sure enough we get that with the doctrine of the two truths. From one point of view there are illusions, i.e. that the physical world is there and it persists, and secondly from another point of view all the things we see in consciousness are empty, and have no reality outside of the suchness of their appearance as aggregates in flux in consciousness. Now in Buddhism the emptiness of conscious phenomena is the reality and the substantiveness and unity of phenomena in consciousness is the illusion. However, emptiness is a nondual state which is defined by the tetralemma (A, ~A, Both and Neither) as something other than its four positions. So that means that the fundamental bedrock of consciousness is inherently nondual and rooted in existence rather than Being (Sat). So then we are left to explain how the illusions arise and persist and this is where karma comes in, but because everything in life is dukkah (dissatisfying and leading to suffering) this is what prompts us to look for something, else like a way out of Karma, which would be Nirvana, the annihilation of the karmic traces.
Karma can be seen as what gives continuity to consciousness, i.e. it is ultimately moment to moment and the idea it is life to live is just a metaphor for the dynamics in consciousness. But at the same time as it is aggregates in flux it is also empty and nondual. The solution to how this can be is that emptiness is not altogether empty, it is not a flat plenum with nothing in it, but rather emptiness has its own inherent structure, which is interpenetration. And we can model that by hypercomplex algebras as in the case of the Emergent Meta-system (seehttp://nondual.net).
What we see is that consciousness is itself based on the Emergent Meta-system dynamic and do we can have a holonomic theory of consciousness based on Special Systems Theory. And from this point of view enlightenment is merely the realization of the fundamental nondual nature of consciousness itself and its dynamic which underlies all perceived and conceptualized phenomena as non-conceptual and non-experiential substrate, which like empty space contains no ether. That is why in rDzogChen the basic analogy of the mind is to empty space. But empty space is Void as defined by Taoism. So the analogy of the emptiness of the mind is the Void of nature. rDzogChen at least in the case of Majushimitra and Mipham deconstructs the idea of the two truths, and uses Nagargunas logic to question this basic assumption of Buddhism that enlightenment is different from normal consciousness. This happens in other forms of Buddhism as well, like Chan (Zen).