The soul, in many religious, philosophical, psychological, and mythological traditions, is the incorporeal and, in many conceptions, immortal essence of a person, living thing, or object. According to some religions, including the Abrahamic religions in most of their forms, souls or at least immortal souls capable of union with the divine belong only to human beings. For example, the Catholic theologian Thomas Aquinas attributed "soul" (anima) to all organisms but taught that only human souls are immortal. Other religions (most notably Jainism and Hinduism) teach that all biological organisms have souls, and others further still that non-biological entities (such as rivers and mountains) possess souls. This latter belief is called animism. Greek philosophers such as Socrates, Plato and Aristotle understood the psyche (ψυχή) to be crowned with the logical faculty, the exercise of which was the most divine of human actions. At his defense trial, Socrates even summarized his teachings as nothing other than an exhortation for his fellow Athenians to firstly excel in matters of the psyche since all bodily goods are dependent on such excellence (The Apology 30a-b). Anima mundi is the concept of a "world soul."