It might be a truism to say that only the absolute can realize itself, that is, the Buddha-nature recognizing itself firsthand. Yes, in one sense it might be true. However, looking at the multifaceted world of avidya or nescience, this present world we are existing in, there is an obvious problem. This problem is illusion and from what, exactly, the illusion is composed (one jewel of many facets). They are not quite the same. Granted that we have the enlightened or Buddha-nature which has never changed in our multifaceted world with its bewitching power to overwhelm us, we are still without a clue as to what this Buddha-nature is. I mean, we can't recognize it even though we have it according to the Buddha.
So what we have here is an absolute nature that remains unchanged which is confronting a phenomenal array of overwhelming bewitching power which appears to have dominion over us. If this were like a Hollywood movie we might be somewhat like Superman who has just received a sufficient amount of kryptonite to render him not only normal, with no super powers, but the kryptonite also caused him to lose his memory. He only knows he is Clark Kent the mild-mannered reporter from the Daily Planet newspaper. How, then , does Clark go about remembering (re-connecting with) his super-nature? Even from this dumbed down example the task is daunting. To reiterate, our Clark Kent is superman having a human experience of working for a newspaper and has not the slightest idea he is Superman.
Much in the same vein, one philosopher put it it this way: "We are not human beings having a spiritual experience; we are spiritual beings having a human experience." In the face of avidya, this requires a lot of faith or hope on our part to accept that we are, first, spiritual beings. This is not easy to do in a world that requires third-person "objective evidence" that can be shared, essentially, with anyone. So, where is there the shareable evidence? There is nothing objective. Therefore, we can safely reject the belief in a Buddha-nature, transmigration of our consciousness, etc., according to third-person standards.
But what if we really are Buddhas who have lost their memory like our Clark Kent? It can't be entirely ruled out. There may come in the future an experiment so, perfectly conceived, that not to accept mind as being primary makes our everyday experience of a phenomenal world impossible. Not yet a reality, our first task is how do we remember our forgotten Buddha-nature? First we have to be persuaded that we have one to discover. This, in itself, is no easy task given the "objective evidence" requirement of our culture. Still, we must go forward and realize this nature by examining the very nature of our thoughts; first understanding that if our thoughts can be stopped for a split second we will come face to face with the absolute which is who we really are. Now we are awake to our super-nature.