Vitarka - Sampatti The literal meaning of Vitarka is contemplation. In yoga the term has been applied with the meaning of cognizing, to the point of identifying with a Sthula (gross) object. In practical terms, it refers to the 'internalisation' of an object that's apprehended. The object can be the sun or moon, a star or image of a deity, etc. through the process of intense meditation. The entire practice is subdivided into savitarka- and Nirvitarka - Sampatti. Savitarka form denotes the identification with an object accompanied by an associated word and concept. Nirvitarka denotes the 'direct', unaccompanied identification with that object of meditation.
Vichara - Samapatti: Vichara sampatti involves making Vritti of the physical object as the object of meditation and dissaolving it in Subtle aspects. The subtle aspect can be that of five tanmantras (subtle principle), avisesas (unparticularised tattva) and ahamkara (ego). As the immediate cause of the tan-matras, aharnkara begins to be brought under control in this samadhi. Vichara Sampatti is the higher level of contemplation, in which non-detachment is cultivated towards the gross aspect of an object. Henceforth, identification with the abstract ground of any particular sense datum begins to occur. This 'abstract ground' consists in the 'soundness' or 'audibility' of a sound, the 'tangibility' of a touch-sensation, the qualities of 'colour-as-such' and 'formness' in a visual object, and so on.
Like vitarka-samapatti, the practice is subdivided into savichara and nirvichara varieties. In Savichara - Samapatti the subtle object is experienced as though conditioned by relations of space, time and cause. Whereas in Nirvichara- Samapatti the same object is not delimited by [such factors], nor limited to those attributes which are apparent only in its present time. All of its possibilities and potentials are realized as being one with an undivided and unitary intelligence (buddhi).
Ananda - Sampatti: Ananda, in spiritual context, signify the supreme and unbroken 'bliss' of absolute awareness. In Samprajnata-samadhi ananda refers to the conditional state of 'rapture' or 'intense happiness' resulting from the transcendence of identification with the tanmatras. In ananda-samapatti, the yogi identifies with ahamkara, the faculty of chitta responsible for identification itself. In other words, self-identity has become centred in the instrument of apprehension, and the vrittis of identification with gross and subtle elements have been dissolved.
Asmita-sampatti: Asmita-samapatti is the final stage of samprajnata-samadhi and consists in identifying oneself with the source of "l-am-ness". The source is the highest, most Sattvika, psychic faculty, namely buddhi or Mahat. The use of the term asmita is slightly confusing, given that it may ordinarily denote the sense of egoity generated by ahamkara. However, In the present context, it should be understood to mean the pure "am-ness" that is still first personal but not egoistic. Vyasa describes the mind in state of Asmita Samadhi as 'pacific and infinite like a great ocean without any waves'.
According to the doctrine codified in the classical yoga texts, the discipline of samadhi creates the systematic dissolution of physical into increasingly subtle vrittis. With each progressive stage of Samprajnata-samadhi comes the Nirodha of vrittis associated with previous stages. In other words, a honing of the practitioner's perception and sense of identity takes place. This enables him or her to move on to more refine 'targets'. Samprajnata-samadhi takes the yogi to the point at which his or her perceptive faculty is acute enough to distinguish between the three essential categories, namely:
(a) The phenomenal manifestations of prakrti (vyakta)
(b) prakrti herself (avyakta).
(c) purusha (self).
The ability to perceive these categories as distinct is called vijnana (special or discriminative knowledge) in the Samkhya-Karika and viveka-khyati (discerning vision) in the Yoga-Sutra. In the process of attining such accurate perspective, the root cause of all vrittis namely "Avidya" is eradicated. Alos, the thought of Purusha nad Prakriti taking as whole is also discontinued. In other words, the existence of the Self must be seen to be unconditional and independent of the phenomenal world. Although viveka-khyati is a prerequisite for the supreme goal of yoga, it is not the goal itself. It induces a highly refined mode of perception, that's least distorted by vritti.