In many religions, philosophical, and mythological traditions, the soul is the incorporeal and immortal essence of a living being. According to Abrahamic religions, only human beings have immortal souls. For example, the Catholic theologian Thomas Aquinas attributed "soul" (anima) to all organisms but argued that only human souls are immortal. Other religions (most notably Hinduism and Jainism) teach that all biological organisms have souls, while some teach that even non-biological entities (such as rivers and mountains) possess souls. The latter belief is called animism.
Greek philosophers, such as Socrates, Plato and Aristotle, understood that the psyche (ψυχή) must have a logical faculty, the exercise of which was the most divine of human actions. At his defense trial, Socrates even summarized his teaching as nothing other than an exhortation for his fellow Athenians to excel in matters of the psyche since all bodily goods are dependent on such excellence (Apology 30a–b).
Anima mundi is the concept of a "world soul" connecting all living organisms on planet Earth.