Monopsychism is the belief that all humans share one and the same eternal consciousness

Consciousness

Consciousness is a term that refers to the relationship between the mind and the world with which it interacts. It has been defined as: subjectivity, awareness, the ability to experience or to feel, wakefulness, having a sense of selfhood, and the executive control system of the mind...

, soul, mind

Mind

The concept of mind is understood in many different ways by many different traditions, ranging from panpsychism and animism to traditional and organized religious views, as well as secular and materialist philosophies. Most agree that minds are constituted by conscious experience and intelligent...

 or intellect

Intellect

Intellect is a term used in studies of the human mind, and refers to the ability of the mind to come to correct conclusions about what is true or real, and about how to solve problems...

. It is a recurring theme in many mystical traditions

Mysticism

Mysticism is the knowledge of, and especially the personal experience of, states of consciousness, i.e. levels of being, beyond normal human perception, including experience and even communion with a supreme being.-Classical origins:...

.

Monopsychism is a doctrine of Sabianism, Jewish Kabbalah

Kabbalah

Kabbalah/Kabala is a discipline and school of thought concerned with the esoteric aspect of Rabbinic Judaism. It was systematized in 11th-13th century Hachmei Provence and Spain, and again after the Expulsion from Spain, in 16th century Ottoman Palestine...

, and Averroism

Averroism

Averroism is the term applied to either of two philosophical trends among scholastics in the late 13th century: the Arab philosopher Averroës or Ibn Rushd's interpretations of Aristotle and his reconciliation of Aristotelianism with Islamic faith; and the application of these ideas in the Latin...

, and is also a part of Rastafarian

Rastafari movement

The Rastafari movement or Rasta is a new religious movement that arose in the 1930s in Jamaica, which at the time was a country with a predominantly Christian culture where 98% of the people were the black descendants of slaves. Its adherents worship Haile Selassie I, Emperor of Ethiopia , as God...

 beliefs. A similar belief in some mystical Jewish and Christian

Christian

A Christian is a person who adheres to Christianity, an Abrahamic, monotheistic religion based on the life and teachings of Jesus of Nazareth as recorded in the Canonical gospels and the letters of the New Testament...

 traditions is that all human beings have different souls but once composed a single unified soul in Adam

Adam

Adam is a figure in the Book of Genesis. According to the creation myth of Abrahamic religions, he is the first human. In the Genesis creation narratives, he was created by Yahweh-Elohim , and the first woman, Eve was formed from his rib...

. Thomas Aquinas

Thomas Aquinas

Thomas Aquinas, O.P. , also Thomas of Aquin or Aquino, was an Italian Dominican priest of the Catholic Church, and an immensely influential philosopher and theologian in the tradition of scholasticism, known as Doctor Angelicus, Doctor Communis, or Doctor Universalis...

disagreed with this belief and devoted most of his writing about Averroism to criticizing monopsychism.