Selfrealization means, of course, to realize the Self. This is very different from realizing the small self, or achieving self-actualization. In fact in Selfrealization, you step out of the small self forever. There are two distinct types of Selfrealization: one without lovebliss and one with. In a strict evolutionary progression lovebliss comes after void.
The Selfrealization project
Getting Selfrealized is the project of a lifetime. It is not something you just do at a couple of "spiritual" weekend seminars and then forget about. You will know when you are stuck in this project, because you will intuitively know that there is a Pure Self that is really you, and you will not rest, ever, until you merge with it.
Preparatory stage. Temporary witnessing
Witnessing is different from self-observation. In self-observation the subject objectifies itself (looks at itself) and this is something everybody can do. In witnessing you step temporarily out of the subject and near into pure being (but not quite). It is characterized by being a witness to your small self, but not yet having consciously realized your real Self in oneness with it. Practicing "being in the now" is an attempt to reach this temporary witnessing (this practice can not take you further into Selfrealization). One could say all meditative practices seek this witnessing-state one way or another, and when you have a good meditation, this is the stage of temporary freedom you reach. If you want to go beyond that, you have to leave the meditation practice behind at just the right moment and merge with the Self. Some meditations may be ecstatic and give rise to cosmic orgasms, but they are not necessarily deeper into the Self. Bliss and ecstasy signify a sudden arousal of kundalini and a rush of shakti through your system. Your bliss may be true lovebliss. To give you a hint about what is what, know that first there is love, then there is bliss and ecstasy, then there is silence in pure being, then there is love-bliss which is both more intense than bliss and ecstasy, yet totally calm and unmoving since it is the unmanifest Self and is causeless and without an object. You do not need ecstatic experiences to reach Selfrealization as Pure Being without love-bliss. But there is no benefit in not developing the bliss of Shakti prior to merging with the Self, on the contrary. Some maintain bliss is a distraction, I say it is not as simple as that, because if the bliss is a symptom of an awakened kundalini, then merge with the bliss by all means and you will reach not only basic Selfrealization sooner, but also move on from there sooner.
The witnessing state
It is possible to reach a state of freedom from identification with the "I", where the identification-mechanism is crushed, yet you are not Selfrealized. This is the witnessing-state. It is the I AM-ness state, where one knows oneself to be nobody, but the most subtle I-ness has not been dissolved. It is easy to believe this state is Selfrealization, since there are no identifications, one witnesses everything, and one has realized oneself as nothing (nobody). But this state is characterized by a duality between self-as-nobody and everything else, and as such it is truly witnessing everything. The self-as-nobody has a very, very subtle sense of being nobody (nothing), and one truly is nobody (nothing), but there still remains an unmanifest sense of I-ness. There will be a sense of "I am nothingness", thus the I is unmanifest. This is the basic I-ness principle. This I-ness is the root of ignorance.
Once I-ness goes away for ever, you are Selfrealized. Selfrealization can be without bliss or it can be with bliss, but it is the same basic freedom from I-ness and oneness with the Self.
Dark Night of the Mind -- Dark Night of the Soul (1)
As witnessing becomes more frequent and deepens, then you enter the Dark night of the Mind. This is what most people call the Dark Night of the Soul, however, it is more a transformation of the mind than of the soul. In this phase you are constantly confronted with how inadequately you understand what Selfrealization is, and you have to constantly admit mental defeat. Ultimately the Dark Night of the Mind is the mind's and the I's fight against you getting free of identification with them. The mind will conceal this fight as an attempt to understand Selfrealization, but basically it is keeping you in bondage. So in this phase you have to relentlessly tell the mind that it can not grasp what Selfrealization is, yet you must try your best to understand. This paradoxical situation is frustrating. You think, you've got it, but then you realize you haven't. On a deeper level, you have meditative experiences which may linger on for a long time in everyday life, and this may trick you to believe you've got it, but this belief is the mind also. Know one thing for sure: If there is ANY sense of an I that has it, you haven't got it. This does not mean that every trace of personality (the I) should vanish, it means that there is no identification and that there is no I-ness left. Only I-ness and identification vanish. After they are gone the I is seen as an empty shell, like a body you are incarnated in.
Witnessing or ecstasy are not spiritual enlightenment
As you meditate, you will experience various states of consciousness -- and again and again you will think: "Ah! This is IT!". It may be Pure Being or ecstatic oceans of love or bliss. These states may be flashes or they may hang on for days or weeks. But they will eventually go away as long as the identification mechanism is intact and you haven't removed the basic I-ness. So, how do you break the identification mechanism? The only way is to merge with the Self. This means you will have to meditate every day. Just going about your everyday life trying to be in the now, Eckhart Tolle-style, will simply not do, for this will never make the basic I-ness vanish. At best it will put you in temporary states of witnessing, but this is so far removed from Selfrealization, that it is barely worth mentioning.
Oneness with the Self can be so complete that you lose consciousness (nirvikalpa samadhi). When you come out of this samadhi, you will realize that something is very different and you will feel great joy. One day you will come out of Nirvikalpa Samadhi, regain consciousness and discover there is no longer an ego to come back to. When this happened to me, I did not even know my name or age for a whole day. In fact, I didn't even know I did not know, until my guru asked me what my name was and how old I was, and I could not answer. Fortunately personality and personal history returned, but I-ness never returned and the identification mechanism was gone. This state of freedom comes in an instant. It is either there or it is not; there is no in-between. You are not more or less free; that is not how it works. But when freedom comes, it may not be dramatic and can even be so subtle, you don't notice what really happened until much later, when the fact can't be denied anymore.
Selfrealization. Nothingness-being. Freedom. Pure Being
Selfrealization is a state of total freedom from the small I where even the primal I-ness has gone (and the witness in witnessing is gone). We call this stage Selfrealization because here the I-ness (and the identification mechanism which depends upon I-ness) is gone and you have attained oneness with the Self as pure being. Here there is no longer a sense of being nobody or being nothing. There simply is pure being. There is no point of awareness, for pure being is awareness without a source. In witnessing there is still a sense of being an awareness. One is not (yet) blissful. In its purity it is a peaceful state, but when you move on it can get very complicated. It takes a long time to bring IT into manifestation in everyday living. In other words, you have attained a state of freedom, but not yet found the love-bliss. You have stepped out of illusion and into pure being, but not yet into recognizing this pure being in everything around you. When the Self recognizes the Self in everything it is lovebliss. But in pure Selfrealization, such a recognition is not (yet) present. Here there is non-duality in the Self, but duality between inner and outer (unmanifest and manifest).
Plain Selfrealization is the death of the small self that was produced by identification with something that is not Self. But the personality does not vanish, it's just not you anymore. Some say the ego has to go away; that is a matter of definition: if you maintain the personality is the ego, then the ego will remain, if you maintain the ego is the sense of I (I-ness), then yes, ego will vanish.
From Pure Being to non-dual love-bliss
Once you are free of I-ness and identification, it is Selfrealization. This does not mean you have got rid of the small self; you have just got out of it by merging with the Self. In fact the small self will feel all the more present as an empty shell and you will probably want to work hard to get rid of it.
If you have not experienced any love-bliss at this point, you will probably be quite content with this state and live happily in it for many years. If, however, you have experienced supreme love-bliss, you will feel an emptiness and a very strong longing to merge with the supreme love-bliss. You may project this longing for supreme love-bliss onto God and thus long intensely for God, but in reality it is a longing for the supreme love-bliss of the Self. Of course, at this point "God" has a completely different meaning than ever before, but that is a little difficult to put into words here.
At this stage, if you want to move on, you simply have to awaken and arouse kundalini and merge into oneness with Shakti on all levels of consciousness and also of the body. When kundalini reaches the heart, you will overflow with love, when it reaches the brain, you will be one with love-bliss and will recognize the Self in everything.
Dark Night of the Soul (2)
The period of transformation from pure nothingness-being to non-dual lovebliss can last a long time and cause many frustrations. It is the real Dark Night of the Soul. I lived in this state 23 years and suffered a lot because of it --also because nobody could tell me, what was going on and nobody respected my state and I was very lonely in a spiritual sense. So there was a lot of social frustration and loneliness. Ironically you are also free from suffering since you are no longer identified with the sufferer. You are of course a permanent witness, much as in the witness-state, though now there is no sense of being a witness.
Basically this phase is a period where the consciousness, you have stepped out of, disintegrates and become transparent. The goal is non-duality with respect to inner and outer, and in order to reach that, anything that hinders the Self from recognizing the Self in everything else, must dissolve. Here kundalini is your greatest ally. Some may fear kundalini because it to them at first seems to be a destructive energy. But what it destroys is ignorance, and as its process progresses, kundalini will manifest as love-bliss. When kundalini finally settles in the brain, you will be living in perpetual love-bliss and realize this to be the Self.
In the primal stage you have pure being which is empty and is not yet realized as what it is: pure bliss (sat-chit-ananda). Second stage begins to unfold only after kundalini has awakened. It is not possible to attain supreme love-bliss without arousing kundalini and merging it in the brain. A major part of kundalini has to reach the brain and stay there for good by merging with the Self. This means you need to develop and purify kundalini's passage up to the brain. Once kundalini settles in the brain, then the remaining unfoldment will go on by itself and there is no need for meditation. This is a state of perpetual bliss. You never lose the bliss, though it may wax and wane for various reasons. You don't even loose it while sleeping..
In this stage of Self realization, you see the supreme Self in everything and this recognition is non-dual lovebliss. It is non-dual because the Self within, the recognition and the Self without are the same. This unity is love-bliss.
Now, since some karma is intact, there is still a personality hanging around, though you know it is not you of course. You will, after Self realization, observe the personality do some strange and silly things and react in ways, that may seem unworthy of love-bliss. That is just karma unfolding and part of the process of the final breakdown of residual "ignorance". As that process goes on, the love-bliss takes you over completely. Later lovebliss may temporarily recede to the background because some transformation is going on inside. So even at this stage lovebliss is not stable.
Just as suddenly as freedom from the small self came about and I-ness vanished, you will suddenly find your kundalini does not leave the brain and you are constantly in a state of love-bliss. This can come as a major breakthrough or it can come rather unnoticed since kundalini may have been in the brain most of the time anyway, so you will only realize after some time that it is a permanent change. But one thing will not go unnoticed, and that is the flash of energy in the brain as kundalini makes the brain its new abode. You will feel the crown chakra opening and as if a million bubbles are exploding inside the brain. And most importantly you will feel like the brain dissolves into Shakti. When you open your eyes after that meditation, you will see the Self in everything around you. So it comes in a flash, but since you may be so used to love-bliss by now, and so used to losing it again, you may expect to lose this also. But one sweet day, it will not leave you anymore.
Yes, there is more beyond this, but let the above suffice for now.