MONOPSYCHISM

Monopsychism  [noun]  a doctrine that there is but one immortal soul of which individual souls are manifestations.    Etymology: from Greek monos, “alone” + psychē, “soul”.  [James R. Eads]

The belief that all humans share one and the same eternal consciousness, soul, mind or intellect. It is a recurring theme in many mystical traditions. Monopsychism is a doctrine of Sabianism, Jewish Kabbalah, and Averroism, and is also a part of Rastafarian beliefs. A similar belief in some mystical Judeo-Christian-Islamic traditions is that all human beings have different souls but once composed a single unified soul.  (Wikipedia.org)