The yogi realizes that the knower, the instrument of knowledge and the known are one, himself. Like a pure transparent crystal jewel, he reflects an unsullied purity.
This stage is called savitarka samapatti. At this stage the word, meaning of the word and the idea of the word are blended and become indistinct (verbal) special knowledge.
When the memory is ceased, the mind shines out as the object alone. The thought transformation becomes distinctive, wordless. This is Nirvitarka Samadhi.
The subtlest level of nature, mulaprakriti is consciousness. This mulaprakriti is the farthest extent of the subtlety.
All these four samapattis have their origin in the external objects; they are dependent upon support or seed.