Brihad Upanishad declares :- Yoga cannot give you truth.

Seeker has to realize the fact that the right path to acquire Self-knowledge or Brahma Gnana or Atma Gnana is the inner (mental) path.   

In the ancient time, religious, Yogic or mystic disciplines, which were not an end in itself, considered to be means for self-realization. But such discipline is almost impossible task for the modern man to adopt. Day by day modern man is becoming aware of the fact that religion and yoga are nothing to do with pursuit of truth. .

The modern mindset is pre-eminently scientific owing to the great progress that science has made. And the best method of freeing the one from his inaccurate ways of thinking is to imbue him as fully as possible with the scientific spirit. It is therefore only one who possesses a clear knowledge of its methods and results i.e., who is able to make reason the highest means of inquiry that would be fit for self-knowledge or Brahma Gnana or Atma Gnana. 

Yoga cannot remove ignorance. It is only a step. It removes obstructions.  Many non-dual masters also declare definitely and says that Yoga is not the means of liberation .The man who knows Spirituality knows the world. Make use of Reason.

One who loses touch with the world and gives himself over to his thoughts alone takes his illusions to be realities and he is in hallucination.

Both sides of life have to be inquired into--the external and internal worlds, mind which is matter and its invisible substance if one is to find truth. Yogi does not includes the world in his inquiry, hence cannot find truth.

 If yogi thinks he does not see the world by shutting his eyes and omitting it from his thought, he is a fool and not Wisdom. If there is nothing to be seen, if mere absence of the external world from cognition gave Atman, then every creature would attain knowledge of truth because it loses the world in deep sleep.

It is not possible by mental control alone, by yoga, to achieve Atman, but at best one falls into a sleep. It is like draining a sea drop by drop, to try the yogic way. He does not examine the phenomenal world and hence cannot grasp Atman for he takes that world as real but runs away from it.

Inquiry and reasoning must begin with experience of duality that is with a world to inquire into. It will end with unity. The yogi tries to avoid this duality by ignoring the world. Hence he gets a false unity only.

The causes, characteristics and nature of Waking experience--these are needed to be studied to-day and the knowledge as it was needed in ancient times.  There is no running away from Atman. It is the only reality. Hence dropping the world is illogical.

After yoga seeker should leave to work at Wisdom. For peace can be gained by deep sleep, by drugs, etc. It is not enough. Hence Ashram will be helpful to gain yogic peace but no more. To visit it may be useful; to linger permanently will be injurious.

Yoga and Mysticism disdain books, F.S rejects nothing but finds all, even religion useful at stages, but says finally come up to Reason. Nothing but reason will finally help to acquire wisdom.

Seeker  indulge in deeper self-search in Oder to know the truth about Yoga  :-

v  “Why do I say that Yoga is right and Spirituality can’t give truth?" 

v  Or how am I to know that Yoga leads to final truth?" 

Yoga and religion are only for beginners; for the more advanced there is reason.  Yoga kills the ability to know intelligently, so that when one believe or are told by Guru that one has seen Atman, there is no means of his understanding whether this is so. This is because Yoga suppresses thinking.

Ultimate truth will interest only few people; the rest will say "they have a religion, why do they have to bother about wisdom?" Religion is that teaching which pleases minds which lack vigor.

The scriptures are for ignorant masses, who wholly accept the Waking experience as it presents itself. Wisdom is for those who have begun to realize that things are not what they seem.

When religionists say that God has sent him his needs through human instruments, how does he know? It is only his imagination.

What is meant by sacred? Cow-dung is treated as sacred in India, but despised by rest of the world where therefore there is a standard of sacredness. Everyone thinks what is sacred according to his own standpoint.

How can the atheist prove the god does not exist, unless one is a fool, he will never be an atheist.  Each sect concocts a God to suit its own purposes:  F.S does not value for such concocted Gods.

Yoga belief is a self-mesmeric condition out of which it is extremely difficult to escape. Man himself suggests that there must be a God. It is an auto-suggestion. 

 Yoga has its place rather than its value and that its value is for a certain type of mind. Yoga will give steadiness of mind, education of mind, but never Truth because it ignores the external world.

One cannot live without the waking  world; it is the basis of one’s life, so it must be the starting point of one’s inquiry. Things, not imaginations, must be the Spiritualists’ material.

Yoga shuts its eyes against the world and then has the temerity to declare that it knows the world to be Atman! Because yogi has not inquired into it, he knows nothing.

Yoga's secret from ultimate viewpoint is this: it helps the yogi by giving him the feeling that the world is not worth bothering about, it detaches him from world; it makes him treat the world as a dream that is an idea. It does the same to his ego to some extent because he becomes indifferent to what happens to him. But the great secret is that this is only feeling, he feels these things only but does not know that the world is an idea. Such knowledge can come only after Spiritualistic inquiry and in no other way. That is why yogi cannot be Wisdom. It is the difference between feeling and knowledge.

Brihad Upanishad declares :- Yoga cannot give you truth. 

BRIHAD UP. Page 133 1st para points out that:-  even yoga cannot give perfect concentration and that the only way to gain it is philosophical realization. This confirms Mandukya's statement that yoga can no more succeed than the ocean can be emptied with a blade of grass. 

Upanishad and one will see that it says Atman the innermost self is known by Reason alone, by sharpened and purified intellect. Yet still people worship Yoga and mysticism as the sole means of attaining Atman. 

Buddha gave up his austerities of yoga as impossible and useless.(Page.70/71 "Buddhism in Translation” by Warren)

Thus Buddha got enlightenment only after he gave up Yoga. Unless one exercises his reason--there is no chance of getting truth.

Ashtavakra says: - “This is your bondage, that you practice Samadhi.

--

Yoga is practiced on the base of physical body. When the yogi sits down to meditate, he is thinking first of his posture, i.e. his body; next he tries to get rid of his thoughts," i.e. he is already thinking of those thoughts. Thus his mind is filled with body and the thoughts (ego) , never of the formless witness.