In Christianity the soul is all important. However, because the Bible does not give a formal definition of the concept, Christian interpretations vary greatly. Under the influence of the Neoplatonists, the soul often came to be set over against the body in a dualistic concept that posited a God-given soul distinct from an inferior, earth-bound body. Scholasticism (specifically that of St. Thomas Aquinas) studied the soul in great elaboration, and the scholastic definition of the soul as "substantial form of the body" obviates many philosophical difficulties. The nature of humanity is involved in the whole consideration of the soul; hence the term "rational soul" for the distinctive soul of humans. The soul of beasts is called the "animal soul" and that of plants the "vegetative soul." The scholastics considered the rational soul alone as immortal and capable of union with God.
The origin of the soul has been a controversial question in Christian history. Two points of view may be distinguished: creationism, which posits that God creates each individual soul in a special act of creation (at the time of conception according to some or that of birth according to others), and traducianism, which suggests that the parents in begetting the child beget the soul too. The creationist principle has been generally held sway in Christianity.