There is only One Existence, and that one the Atman, the Self; and when this is perceived through the senses, through sense-imageries, It is called the body. When It is perceived through thought, It is called the mind. When It is perceived in Its own nature, It is the Atman, the One Only Existence.
(“One Existence Appearing as Many”, Complete Works of Swami Vivekananda, Vol 3)