Drg-Drshya-Viveka 23

"The practice of meditation within is of two kinds: with duality and without duality. The meditation with duality is again of two kinds: that which is associated with the seen and with words." - Verse 23

Excerpt From Commentary:

Vikalpa means duality - That which remains with duality is savikalpa. The practice of meditation maintaining the duality of the meditator and the meditated upon is called savikalpa samadhi. This duality is also seen in upAsana, where the attributes of the Lord (saguna brahma) are worshipped. In savikalpa samadhi, the meditator is the empirical jiva - the limited individual and the object of meditation is the attributeless Self. this duality, of the meditator and the meditated upon, exists in the practice stage. Once this duality disappears, the Infinite Self alone remains. This is called nirvikalpa samadhi. The practice of savikalpa samadhi culminates in nirvikalpa samadhi.

It should be noted that the Self is always nirvikalpa, non-dual. It is the mind that creates duality. Once the mind is transcended, nirvikalpa samadhi is attained. An example of sleep illustrates this point.

Tired after a day's labor, a man reaches his home. He showers, has dinner, maybe watches TV for some time and then retires to bed. He makes himself comfortable in bed and slowly withdraws from the familiar world around him. His attention withdraws from the body. He wants nothing but sleep. Till the thoughts, 'I am sleepy', 'I want to sleep' remain, he is not asleep. There still remains the duality of one wanting to sleep and the state of sleep. Once sleep overpowers him, all dualities end. We can never determine the exact time when we sleep. If the thought of time remains, then we are awake - we glide unknowingly into sleep. Efforts can be put forth only to prepare for sleep. It is only when all efforts end, that we fall asleep.

Similarly, the meditator meditates on his own nature - I am Existence-Consciousness-Bliss, the illuminator of all thoughts. This thought of knowledge is not a sentence picked up from a book, but is the result of discrimination between the Seer and the seen, and enquiry into their natures. Efforts are put forth until the state of savikalpa samadhi is attained. This thought eventually disappears, and the meditator glides into nirvikalpa samadhi. In sleep, the thought of duality is overpowered by tamas - inertia, whereas in samadhi, it merges in the Pure Self.

The meditator is a non-existing, superimposed, entity. The object of meditation is the very subject which illumines all objects, and the practice of meditation is a suicidal act on the part of the meditator! 

Meditation has to be practised only because we have somehow come to believe ourselves to be contrary to what we are.