There are many forms of dark nights... In a more technical sense, there are two of them, and in a loose - daily - sense, lots of them.
The two formal ones are...
- The dark night of the senses, which is an initial stripping away of beliefs and identities, enough to notice all as God, to notice that everything is a field of awakeness, of consciousness, even of awake emptiness. It can be painful, maybe an experience of being pulled apart, dismembered, even of dying. What dies is really only beliefs and identities, but when we are identified with these, when we take ourselves as that, the experience is of being dismembered and dying. For me, this was a very intense time, but there were lots of rewards in the middle of it as well. It was painful, but also immensely blissful.
- The dark night of the soul, which is similar but goes more to our core beliefs and identities, and specifically the one of a separate self, of someone that this is all happening to. Here, any and all beliefs are stripped away, and it often happens through a profound disillusionment. Everything that we found comfort in is stripped away, taken away from us, and none of our practices have meaning or even work anymore. Nothing is left. God is gone. Any sense of accomplishment is gone. Any ideas of being special, or chosen, are gone. There is no place to anchor any of those beliefs anymore. They get stripped away, whether we want or not, and most often we desperately cling to them as long as we can, making the torment even stronger for ourselves.
And having cleared out even more, including the sense of a separate self, through the dark night of the soul, the emptiness is revealed in its completeness. When I am gone, emptiness is revealed, as the Ground of it all... of awakeness itself, of the soul level, of mind, of form. It is all emptiness dancing, already and always absent of any trace of any separate self anywhere.
Our core belief, and core identity, of a separate self is greatly diminished through the dark night of the senses, and that is exactly what allows the soul realm to be noticed and come more into the foreground. Here, there can be a sense of no separation, of all - absolutely all - as God, as divine, as consciousness, as the divine mind, there can even be a sense of oneness, but there is still a trace of a sense of a separate self here. And this serves as an anchor for a sense of being special, privileged, of having accomplished something, of being chosen.
The dark night of the soul takes care of that. Every reason for feeling special, privileged, of having accomplished something, of being chosen, is taken away. And none of the practices or tools that at one point work so easily and so well, have any use anymore. They are all broken.
Where the dark night of the senses is more of a dismemberment and a sense of dying as a human being, the dark night of the soul is a deep existential falling away... my most core identity of being something at all, separate from anything else, is wrestled away... leaving just emptiness. No angels. No luminosity. No bliss. Nothing special. Just emptiness. The emptiness that allows, and is, the dance of everything.
The dark night of the senses leads into an amazing awakening, with lots of bells and whistles... God in all its glory. Alive luminosity. Guidance. Inner God, and all as God. Amazing insights. Amazing abilities to do things in the world. Amazing energies.
The dark night of the soul leads into nothing at all. At the threshold of it, it appears thoroughly boring, neutral, like nothing. And inside of it, there is the Ground of all, that which allows the dance of everything. It is nothing special. Just what is, here and now, always.
The void that never changes, and allows all change. The no-thing that allows all things. The absence of everything which allows the fullness of everything. The groundless ground, which already and always allows every fruit.
The bottom falls out of everything. Leaving only the dance of emptiness, with no separate I anywhere.