Smadhi is last step of Ashtanga yoga. When we succeed in becoming so absorbed in something that our mind becomes completely one with it, we are in a state of samadhi. Samadhi means “to bring together, to merge.” In samadhi our personal identity-name, profession, family history, social security number, driver’s license number etc.-completely disappears. In the moment of samadhi none of that exists anymore. Nothing separates us from the object of our choice; instead we blend and become one with it.
During samadhi, we realize what it is to be an identity without differences, and how a liberated soul can enjoy pure awareness of this pure identity. The conscious mind drops back into that unconscious oblivion from which it first emerged. The final stage terminates at the instant the soul is freed. The absolute and eternal freedom of an isolated soul is beyond all stages and beyond all time and place. Once freed, it does not return to bondage.
Thus, samadhi refers to the union of the contemplating being with the object of contemplation. Here, the object of the meditation and the meditator become one. This is like the unity of process; it is like the union of function and structure. The polarity of viewer and viewed, like the polarity of opposites, is no longer relevant; the mind does not distinguish between self and non-self, or between the object contemplated and the process of contemplation. There are various stages of samadhi, depending upon whether one is identified with the object while yet conscious of the object, or whether one has transcended the object of meditation and is resting in the experience of being, without conceptual support or without support of any aspect of Consciousness.
Pratyahara, dharana, dhyana, and samadhi cannot be practiced. A person cannot simply sit down and say, “Right now I am going to do dharana.” All the person can do is to create the right conditions to help bring about a state of dharana; For example, he or she can practice asanas and pranayama that, according to the Yoga Sutra, create favorable conditions for the mind to enter these states. In order to experience dharana and dhyana, the mind must first be in a particular condition. Allow the many things that are going on in the mind to settle so that it becomes quiet. If the mind is too busy responding to external stimuli, it cannot enter into a state of dharana. Forcing dharana when your mind is not ready for it can get you into trouble. For this reason the Yoga Sutra suggests the practice of asanas and pranayama as preparation for dharana, because these influence mental activities and create space in the crowded schedule of the mind. Once dharana has occurred, dhyana and samadhi can follow.
The perfection of samadhi embraces and glorifies all aspects of the self by subjecting them to the light of understanding. The person capable of samadhi retains his or her individuality and person, but is free of the emotional attachment to it./