Guilt by Identification
At the time of the development of the various versions of the doctrine of original sin, there was a live debate regarding the origin of souls. Each person was believed to have their own soul, but where this soul came from was a point of contention.
Creationists held that as a new person developed in the womb, so a new soul was created. They were opposed by Traducianists, who believed that a new child began life with a part of his or her father’s soul. This latter view provides the basis for an explanation of the Fall and original sin.
According to Traducianists, there was a time when there was just one soul, that of Adam. When Adam sinned, this soul was corrupted. All human souls that have come into existence since have not been created from nothing, but rather are â€˜cuttings‘ from Adam’s corrupted soul. In this sense, we are thought to have â€˜been Adam‘ at the time of the first transgression, and so are also thought to be guilty of that sin and subject to just punishment for it.
Though this view has its place in the history of the doctrine of original sin, it has not aged well, due to its reliance on a strange form of dualism involving divisible souls.