which the unity of a mind is regarded as a matter of degree, and not a matter of all or none; and a mind, such as your mind or mine, is regarded as a very complex series of interlinked mental events, some of which are conscious experiences, and others subconscious or unconscious. This suggestion would be compatible with the tripartite division of human nature into Body, Mind and Spirit which some religious thinkers, both eastern and western, have advocated. On this tripartite theory, the remarks in the text would apply to mind, but not to spirit.
My conclusion, then, is this: if the paranormal facts compel us to abandon the materialistic conception of human personality, and if we are therefore inclined to adopt a dualistic interaction theory instead, we must be careful to dissociate the interaction theory from the substantialist conception of mind which has been historically associated with it. If we do retain the substantialist conception of mind, our dualistic theory will be as irreconcilable with the paranormal facts as any of the materialistic theories are. Indeed, I am inclined to think that the unconscious influence which the in divisible-mental-substance theory still has upon our thinking is at present the greatest single obstacle to the progress of parapsychology on its theoretical side. It has an inhibiting influence on our inventive powers and prevents us from constructing the new and no doubt very strange explanatory ideas which we need for making sense of the new and strange facts which parapsychologists have discovered.