Monopsychism

Monopsychism is the belief that all humans share the same eternal consciousness, soul, mind and intellect. It is also a recurring feature in many mystical traditions.
Monopsychism is a doctrine of Sabianism, Jewish Kabbalah, and Averroism, and also forms a part of the Rastafarian belief system.
Aquinas.
Thomas Aquinas disagreed with this belief and devoted most of his writing to Averroism and criticized monopsychism. One of his works, a commentary on Aristotle's "On the soul", is titled "De unitate intellectus contra Averroistas". In this commentary, Aquinas demonstrates how Averroes misinterpreted Aristotle's argument, claiming that the correct interpretation was that an individual's intellect cannot be independent of his or her physical body.