The four समाधिः viz. वितर्क, विचार, आनन्द and अस्मिता known as संप्रज्ञात-समाधि are also known as सबीज-समाधि since they occur in association with the बीज, i.e. object of perception.”
This was stated before in Yoga Sutra 1.17: वितर्कविचारानन्दास्मितारूपानुगमात्सम्प्रज्ञातः॥१७॥ and Yoga Sutra 1.46: ता एव सबीज: समाधिः॥४६॥
सवितर्क and निर्वितर्क are concerned with gross objects while सविचार and निर्विचार are concerned with subtle objects.
निर्विचारवैशारद्येऽध्यात्मप्रसादः॥४७॥ (Yoga Sutra 1.47)
“When निर्विचार is perfected, there follows the purity of the internal organ (mind)”
Though both सवितर्क and निर्वितर्क have gross objects as their content, the निर्वितर्क, which has the nature of being free from विकल्प, is still superior to सवितर्क, which is mixed up with विकल्प between word, meaning and ideation.
Superior to that is सविचार, which is concerned with subtle objects and in which they are revealed in assocition with विकल्प.
Superior even to that is निर्विचार, which is concerned with subtle objects and in which they are revealed unassociated with विकल्प.
Among them, the preceeding three, being meant to lead to the निर्विचार become fruitful by the fruitfulness of the निर्विचार itself.
However, when the निर्विचार समाधि becomes perfected through the power of intense practice, and the quality of सत्व unimpeded by रजस् and तमस्, becomes dominant, ‘there follows purity of the internal organ’; in that mind, which is devoid of the impressions of क्लेस (pain bearing obstructions), there arises the clear light of insight (प्रज्ञा) with regard to an object as it is in its totality, without any sequential comprehension.
On this Vyasa comments: “The sorrowless man of insight, after attaining the ‘clarity of insight’, looks upon all the sorrowful people as does a man on a mountain peak the people on the ground.”
ऋतम्भरा तत्र प्रज्ञा॥४८॥ (Yoga Sutra 1.48) “The insight gained there is called ऋतम्भरा (filled with truth).
‘There’, when the purity of the mind is gained, the insight (प्रज्ञा) that comes to the yogi whose mind is in the state of absorption is called ऋतम्भरा–that which contains truth only, in which there is not even a trace of error.
The term ऋतम्भरा is indeed a derivative term. And that निर्विचार समाधि is a high state of Yoga.
On this Vyasa states: “One attains the high state of Yoga by cultivating प्रज्ञा in three ways. Through scriptural texts (i.e. through श्रवण, अनुमान i.e. inference–मनन, and a liking for the practice of meditation known as निदिध्यासन.”
श्रुतानुमानप्रज्ञाभ्यामन्यविषया विशेषार्थत्वात्॥४९॥ (Yoga Sutra 1.49)
But that ऋतम्भरा प्रज्ञा is different from the knowledge gained through hearing (श्रुत) and inference (अनुमान), because it relates to specific characteristics of objects.
श्रुत means scriptural knowledge. That relates to objects in a general way only.
For, it is not possible to comprehend any relationship between a word and the specific characteristics of the object denoted by that word.
Similarly, inference relates to objects in a general way only; for it is not possible to understand the specific characteristics of an object through a knowledge of व्याप्ति (invariable concomitance).
For example, from the general knowledge that ‘fire exists wherever there is smoke’, one may infer that at a certain place ‘there is fire because smoke is also seen there’. But from this inference he will not know the particulars of that fire.
Therefore no specific characteristic can be an object of scriptural and inferential knowledge.
Besides, there is no direct knowledge of this subtle, hidden and remote entity through ordinary perception.
But that specific characteristic, be it of some subtle element or of the Person, does become clearly comprehended through insight gained in समाधि.
Therefore great effort has to be put in by a yogi for the ऋतम्भरा प्रज्ञा itself, insight that is filled with truth, which arises on the perfection of निर्विचार समाधि.
This निर्विचार समाधि is different from the knowledge gained from scriptural text and inference; and whose contents are all the specific characteristics, be they subtle, hidden and remote. This is the idea.