Investigate what the mind is and it will disappear

"Investigate what the mind is and it will disappear, There is no such thing as 'mind' apart from 'thought.' There is no use removing doubts. If we clear one doubt another arises, and there will be no end of doubts. All doubts will cease only when the doubter and his source have been found. Seek for the source of the doubter, and you will find that he is really non-existent. Doubter ceasing, doubts will cease."