Here is the main issue as I see it: One may have a permanent realization of the void. It doesn't matter whether science, philosophy, psychology, or neuroscience has a problem with such a claim. Does everything need to be proven to the nth degree?
Perhaps we only have a problem if one tries to manipulate others, profit from their claims, or cause suffering due to their stance. Religion does all three, which is why it cannot be allowed to run amok. Spirituality is often no more than a strangely disguised form of religion, and nestled within spirituality are many so-called mystics. When spirituality produces psychics who charge for their services, I take no issue with such a service. However, if they were to influence legislation, public services, etc., then they'd have to do a lot more than just make a claim that they are psychic and should be trusted.
But for someone like me it makes no difference whether anyone believes me, agrees, or even disagrees. None of this affects my own reality or my experiences. My claim that I realize the void is something that anyone else can find out through their own observation. I don't lead classes or dictate to others what they should do and how to behave. And perhaps the reason is because I see that everyone is in the same boat, which is living life through the senses of the egoic self.
Perhaps one of the greatest metaphors is Plato's allegory of the cave: We are so conditioned to believe what we think is reality that we cannot see the truth about our own conditioning. This, I am pretty sure, can be proven. But where is the cave, the experience, and the prisoners? It is within the void.