Sri Aurobindo
Letters of Sri Aurobindo
Volume 1
Yes, let your sister decide these things for herself; do not put any pressure upon her.
There is no reason why one should not receive through the thinking mind, as one receives through the vital, the emotional and the body. The thinking mind is as capable of receiving as these are, and, since it has to be transformed as well as the rest, it must be trained to receive, otherwise no transformation of it could take place.
It is the ordinary unenlightened activity of the intellect that is an obstacle to spiritual experience, just as is the ordinary unregenerated activity of the vital or the obscure stupidly 
obstructive consciousness of the body. What the Sadhaka has to be warned against is, first, mistaking mental ideas and impressions or intellectual conclusions for realisation; secondly, the restless activity of the mere mind, chanchalaṃ manaḥ which disturbs the spontaneous accuracy of psychic and spiritual experience and gives no room for the descent of the true illuminating knowledge or else deforms it as soon as it touches the human mental plane. Always, it is substituting its own representations and constructions and opinions for the true knowledge. But if the intellect is surrendered, open, quiet, receptive, there is no reason why it should not be a means of reception of the light or an aid to the experience of spiritual states and an inner change.