There is only one mind and all such names as cosmic mind, over-mind, and so forth are merely imperfect and partial concepts of that ultimate single mind which philosophy puts forth in order to help students advance to a higher stage. These concepts are not false, however. They represent aspects of the same ultimate mind as seen from different standpoints. As these standpoints are not the highest they do not yield the final truth. It will be well therefore for him to accustom himself to the highest standpoint and to remember always that there is but one mind, one reality, one principle, one substance, one being only. All things are forms or shapes which it appears to take temporarily. The key to the understanding of these admittedly difficult points is to think of the universe seen during dream and then to remember that that universe itself, its seas and continents, its peoples and animals, its happenings in time, its distances in space, do not exist apart from the mind of the dreaming person; that even if millions of people exist within that universe they are nothing else than ideas passing through the mind of the dreamer; and that their ultimate stuff or reality is mind although to the dreamer they appear real, as do also water, fire, gas, and even the ninety-odd chemical elements. Now he must try to regard the waking universe in the same way, with this difference: that because the ego is one of the dreamed-of figures in the waking dreams it must be eliminated if one is to break through the dream and ascertain that it is a dream in the universal mind.
-- Notebooks Category 21: Mentalism > Chapter 3: The Individual and World Mind > # 44