' single mental ground '...

The student must for minutes deliberately recall himself from the external multitude of things to their single mental ground in himself. He must remind himself that although he sees everything as an objective picture, this picture is inseparable from his own mind. He has to transcend the world-idea within himself not by trying to blot it out but by thoroughly comprehending its mentalist character. He must temporarily become an onlooker, detached in spirit but just as capable in action... — Notebooks Category 23: Advanced Contemplation > Chapter 7: Contemplative Stillness > # 211 Paul Brunton