Q: Is it not good to acquire powers such as telepathy?
Ramana Maharshi: Telepathy or radio enables one to see and hear from afar. They are all the same, hearing and seeing. Whether one hears from near or far does not make any difference to the one who hears. The fundamental factor is the hearer, the subject. Without the hearer or the seer, there can be no hearing or seeing. The latter are the functions of the mind. The occult powers [siddhis] are therefore only in the mind. They are not natural to the Self. That which is not natural, but acquired, cannot be permanent, and is not worth striving for.
These siddhis denote extended powers. A man is possessed of limited powers and is miserable. Because of this he wants to expand his powers so that he may be happy. But consider if it will be so. If with limited perceptions one is miserable, with extended perceptions the misery must increase proportionately. Occult powers will not bring happiness to anyone, but will make one all the more miserable.
Moreover what are these powers for ? The would-be occultist [siddha] desires to display the siddhis so that others may appreciate him. He seeks appreciation, and if it is not forthcoming he will not be happy. There must be others to appreciate him. He may even find another possessor of higher powers. That will cause jealousy and breed unhappiness.
Which is the real power ? Is it to increase prosperity or bring about peace? That which results in peace is the highest perfection [siddhi].
Source: Be as you are – The teachings of sri Ramana Maharishi Book