Samprajnata Samadhi or concrete meditation is that which is accompanied by argumentation, deliberation, happiness, egoism and form.
Samadhi is of two kinds viz., Samprajnata and Asamprajnata. Samprajnata Samadhi is the first step. In this Samadhi, Samskaras are not destroyed. This is also known as Sabija Samadhi, because the seeds or the Samskaras are there. In this there is Alambana or support.
In Samprajnata Samadhi there are four varieties viz., Savitarka, Savichara, Sananda and Asmita. All these will be explained in the subsequent Sutras. Samadhi can also be divided into two kinds, Sthula (gross) and Sukshma (subtle) that relates to Tanmatras and Indriyas. Samprajnata and Asamprajnata Samadhis are termed as Savikalpa and Nirvikalpa Samadhi by Vedantins and Bhaktas.
This Sutra refers actually to a series of meditations in an ascending order, first on the physical universe, then the subtle universe of potentials called Tanmatras, the cosmic complex known as space and time and cosmic Self sense leading to a bliss born of pure consciousness. Though the Sutra refers only to Vitarka, Vichara, Ananda and Asmita, they are further capable of categorisation as involved in space-time consciousness or not involved in space-time consciousness. These stages are intricate and cannot be understood by merely a study of books.
(2) SAVITARKA SAMADHI
There the concentration in which the options of word, meaning and understanding are confused is called Savitarka Samadhi or the Samadhi with argumentation.
If you concentrate and meditate on the gross objects, on their nature and in relation to time and space, it is Savitarka Samadhi (Samadhi with argumentation). It is Sthula Dhyana. You will get control over the object. You will acquire full knowledge of the object. You will get psychic powers (Siddhis).
The 'cow ' as a word, the 'cow' as an object and the 'cow' as an idea, though different from one another, are cognised as indistinct. You begin to analyse. The characteristics of the word are different; the characteristics of the idea are different; and the characteristics of the object are also different. Everything has a name which has some meaning. When the mind apprehends a word and meditates on its meaning and form as well as on the understanding of both, and thus lose itself in the thing completely, it is called Savitarka Samadhi. Sound causes vibration in the mind. It is carried through the external auditory meatus (external opening of the ear), through the auditory nerve to the auditory centre of the brain. Now a reaction takes place. The mind reacts. It understands the meaning of the sound. Now knowledge manifests. Now comes perception or cognition of the object. The mixture of these three, sound, meaning and knowledge constitute perception or cognition of an object. It is Savitarka Samadhi.
(3) SAVICHARA SAMADHI
If you meditate on the subtle Tanmatras, on their nature and in relation to time and space, it is Savichara Samadhi (Samadhi with deliberation). This is Sukshma Dhyana. You will get knowledge of the Tanmatras. You will have great control over Tanmatras. Savitarka, Nirvitarka, Savichara and Nirvichara are called Grahya Samapatti.
(4) SANANDA SAMADHI
If you give up the gross and the subtle elements, if you fix the Indriyas in their respective places and if you give up the gross and the subtle meditation, and if you meditate on the Sattvic mind itself, it is known as Sananda Samadhi. This is called Grahya Samapatti, cognition of the instrument of cognition.
(5) ASMITA SAMADHI
When the Sattvic ego only remains during deep meditation, is called Asmita Samadhi. There is only Prajna of 'Aham-Tvam' in this Samadhi. The Yogi who has reached this stage is a Videha (without body). Prakriti- layas are those who in this state get themselves merged in nature. You will have to proceed further if you want Kaivalya. This is called as Grahitri Samapatti, cognition of the knower.
Savitarka is gross Samadhi. Savichara is subtle Samadhi. Sananda is deep subtle Samadhi. Asmita is still more deep subtle Samadhi. These are all stages like the steps of an ascending stair-case.
(6) SABIJA SAMADHI
These only, viz., Savitarka, Savichara Sananda and Asmita are Sabija Samadhi or Samadhi with seed (Samskaras).
The seeds are the Samskaras of past actions which give birth and death. These meditations cannot give full security. They cannot ensure final liberation, as the seeds are not fried or destroyed. They have got Alambana (support) on external objects, gross or subtle. Niralambana, Nirbija Samadhi only can give the final salvation.