Sage Sankara says: - Yoga is not the means of liberation +

Sage Sankara said:~Neither by the practice of yoga nor philosophy, nor by good works nor by learning, does liberation come, but only through the realization that Atman and Brahman are one in no other way. 1-VivekaChudamani v 56, pg 25

What happens when thoughts are stilled? It is not the ultimate truth that is found.  Thoughtlessness is not wisdom or Gnana. It is only ignorance.

Patanjali yoga is not Atma  Gnana and, therefore, yoga will not yield the highest truth. The yoga is good to give peace and concentration, but only in order to start reasoning, i.e. thinking again and again to find the truth, which is beyond the form, time, and space.

Yoga and Samadhi are not a goal but a means to an end, i.e. Gnana. Samadhi in itself is useless because the mind is withdrawn and there is no memory of it until after it is over and one returns to the waking state. A yogi who attains mind control: it is only sleep.

In Gita Chap.IV where Lord Krishna says: ~ "This yoga has been lost for ages" the word yoga refers to Gnana yoga, not other yogas: the force of the word this is to point this out.

Lord Krishna describes some of the other yogas but devotes this chapter separately to Gnana Yoga. So one sees even in those ancient days people did not care for Advaita; they wanted religion; hence, Gnana got lost. That is why Krishna calls it "the supreme secret." Krishna points out that yoga must see "Brahman in action. 

Bhagavan Buddha: ~ Do not believe in anything merely on the authority of your teachers and elders. 

The path of truth is the path is verification. Nothing has to be accepted as truth without verification. 

Ashtavakra Gita: ~ The fool tries to control the mind with the mind - what folly! The wise one delights in the  Self alone. There is no mind to master.

Sage Sankara says: - Yoga is not the means of liberation. (page 132-133 - Commentary on Brihadaranyakopanishad).

Yoga can yield only the duality because everything that one can do or practice becomes a vanishing 'known.' It yields relative truth based on imagination, which is true from the physical point of view, not the non-dual truth, which is the ultimate reality.

Yoga does not yield truth, because it ignores the objective world.  Say the yoga has its place rather than its value and that its value is for a certain type of mindset.  One cannot live without the physical world; it is the basis of his life, so it must be the starting point of his inquiry. Things, not imaginations, must be the seeker’s material.

The yogi, who follows Patanjali-yoga, wants to sit in a place and think "I’ am shutting my eyes, ‘I’ am sitting in this cave, and ‘I’ am meditating." This egocentric yoga has nothing to do with the ultimate truth or Brahman or God in truth.

The yogi mystic is always thinking in terms of me and ‘I’ for he thinks of what he is to get from his practice; whereas in the path of wisdom one first verifies and get rid of this ‘I’ by the deeper inquiry for he wants the truth, not something for the Self.

The Yogi says he wants to gain Samadhi. The Gnani wants to gain nothing for he knows, "I’ is the whole universe. 

Remember:~

Yoga is meant for the mass mindset, which is incapable of investigating and verifying their inherited beliefs.  The path of wisdom or truth is to get the pure essence of nonduality or Advaita.

In Sutra Bashya and Mundaka: ~ Samadhi and sleep are identical. 

Brihad Upanishad does not advocate Samadhi.

Avadhuta Gita: ~ “The Atman cannot be purified through the practice of the six limbs of the yoga, or through the annihilation of the mind, or through the instruction of a teacher. The Atman is the Reality Itself and It is Purity Itself."

From the standpoint of the Soul, the Self, the visions, and Samadhi are the illusion because they are based on the false self (ego) within the false experience (waking).

It is not possible to stop the thought for more than a half-second whilst in the waking state. If one succeeds in controlling thought and then banishes it, one passes into Nirvikalpa Samadhi, which is identical to deep sleep. The only difference between ordinary deep sleep and Samadhi, therefore, is that the ordinary man falls asleep involuntarily whereas the yogi has the satisfaction of knowing that he has passed into sleep by his own effort of will in banishing thoughts.

Sage Patanjali warns against sleep as a hindrance to yoga, he means when it occurs in the early stages of the practice before one has obtained the power of control and consequently to banish the thought. The fact, that Samadhi is deep sleep is kept secret because people would not be tempted to take up yoga.

Yoga sharpens the ego, to enable it to keep away all extraneous thoughts when one gets out to reason in the practice of the next higher stage, i.e. Gnana.

Yoga is thus simply a sharpening-stone for the ego to enable it to take up Gnana. But you say that Maharishi lives without thoughts, Impossible. How can he walk from one spot to another without thought? He does not know the Gnanic truth if he says thoughtlessness is the perfect stage of the Soul, the Self.:~Santthosh Kumaar