Jung founded a new school of psychotherapy, called analytical psychology or Jungian psychology. His theories include:

The concept of introversion and extraversion (although he did not define these terms as they are popularly defined today).[32] The concept of the complex.

The concept of collective unconscious, which is shared by all people. It includes the archetypes.

Synchronicity as a mode of relationship that is not causal, an idea that has influenced Wolfgang Pauli and some other physicists.

Jung's primary disagreement with Freud stemmed from their differing concepts of the unconscious. Jung saw Freud's theory of the unconscious as incomplete and unnecessarily negative. According to Jung, Freud conceived the unconscious solely as a repository of repressed emotions and desires. Jung agreed with Freud's model of the unconscious, what Jung called the "personal unconscious", but he also proposed the existence of a second, far deeper form of the unconscious underlying the personal one. This was the collective unconscious, where the archetypes themselves resided, represented in mythology by a lake or other body of water, and in some cases a jug or other container. Freud had actually mentioned a collective level of psychic functioning but saw it primarily as an appendix to the rest of the psyche.Jung considered individuation, a psychological process of integrating the opposites including the conscious with the unconscious while still maintaining their relative autonomy, necessary for a person to become whole.

Jung's work on himself and his patients convinced him that life has a spiritual purpose beyond material goals. Our main task, he believed, is to discover and fulfill our deep innate potential. Based on his study of Christianity, Hinduism, Buddhism, Gnosticism, Taoism, and other traditions, Jung believed that this journey of transformation, which he called individuation, is at the mystical heart of all religions. It is a journey to meet the self and at the same time to meet the Divine. Unlike Sigmund Freud, Jung thought spiritual experience was essential to our well-being. Besides achieving physical and mental health,people who have advanced towards individuation tend to be harmonious, mature and responsible. They embody humane values such as freedom and justice and have a good understanding about the workings of human nature and the universe.