Sri Aurobindo
Letters on Yoga
4. Reason, Science and Yoga
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As to doubts and argumentative answers
to them, I have long given up the practice as I found it perfectly useless. Yoga is not a field for intellectual argument or dissertation. It is not by the exercise of the logical or the debating mind that one can arrive at a true understanding of yoga or follow it. A doubting spirit, “honest doubt” and the claim that the intellect shall be satisfied and be made the judge on every point is all very well in the field of mental action outside. But yoga is not a mental field, the consciousness which has to be established is not a mental, logical or debating consciousness – it is even laid down by yoga that unless and until the mind is stilled, including the intellectual or logical mind, and opens itself in quietude or silence to a higher and deeper consciousness, vision and knowledge, sadhana cannot reach its goal. For the same reason an unquestioning openness to the Guru is demanded in the Indian spiritual tradition; as for blame, criticism and attack on the Guru, it was considered reprehensible and the surest possible obstacle to sadhana.
If the spirit of doubt could be overcome by meeting it with arguments, there might be something in the demand for its removal by satisfaction through logic. But the spirit of doubt doubts for its own sake, for the sake of doubt; it simply uses the mind as its instrument for its particular dharma, and this not the least when that mind thinks it is seeking sincerely for a solution of its honest and irrepressible doubts. Mental positions always differ, moreover, and it is well-known that people can argue for ever without one convincing the other. To go on perpetually answering persistent and always recurring doubts such as for long have filled this Ashram and obstructed the sadhana, is merely to frustrate the aim of the yoga and go against its central principle with no spiritual or other gain whatever. If anybody gets over his fundamental doubts, it is by the growth of the psychic in him or by an enlargement of his consciousness, not otherwise. Questions which arise from the spirit of enquiry, not aggressive or self-assertive, but as a part of a hunger for knowledge can be 
answered, but the “spirit of doubt” is insatiable and unappeasable.
Current publication:
Sri Aurobindo. Letters on Yoga // SABCL.- Volume 22. (≈ 28 vol. of CWSA).- Pondicherry: Sri Aurobindo Ashram, 1971.- 502 p.
Other publications:
Sri Aurobindo. Letters on Yoga. I // CWSA.- Volume 28. (≈ 22 vol. of SABCL).- Pondicherry: Sri Aurobindo Ashram, 2012.- 590 p.
[Largest or earliest found passage: ] Sri Aurobindo. The Mother with the Letters on the Mother // CWSA.- Volume 32. (≈ 25 vol. of SABCL).- Pondicherry: Sri Aurobindo Ashram, 2012.- 662 p.
Sri Aurobindo. Letters of Sri Aurobindo: In 4 Series.- Forth Series [On Yoga].- Bombay: Sri Aurobindo Sircle, 1951.- 652 p.