The mind can become quiet only when you detach yourself from it and see the thoughts as things that pass. Then you don’t think yourself but see thoughts passing through your mind. Afterwards you can stop attending to these passers-by and concentrate on the Mother.
Thoughts and feelings are passing from one human being to another all the time, only people don’t know or observe it. Especially if people live together the same life, as in the Asram, a sort of atmosphere is formed in which the same thoughts and feelings are moving about and constantly passing from one to another.
You have to become conscious—that is to say, there must be something in you which is not carried away by thoughts and feelings, but looks at them and observes how they work and how they affect you. The part that observes and knows is called the Witness sākṣī in man. It is always possible to develop this in oneself.
It is not by thinking and reading that consciousness comes. There are many who read and think a great deal but are not conscious, have not the witness developed in them. There are others who work all day like X, yet are very strongly conscious. When one has the power of stopping thinking altogether and only looking, then the Witness becomes very strong and conscious. This consciousness can come by practice, but it can also come by turning to the Mother and thinking of her always and offering to her everything. The being opens, the Mother’s force begins to work and one becomes more and more conscious.
Ref : Letters on Yoga Vol. III