In Miracles Lewis spoke further about Man’s being a “composite being,” having both a supernatural component and a Natural, physical component:
Man must therefore be a composite being - a natural organism tenanted by, or in a state of symbiosis with, a supernatural spirit. . . . whenever we think rationally we are, by direct spiritual power, forcing certain atoms in our brain and certain psychological tendencies in our natural soul to do what they would never have done if left to Nature. The Christian doctrine would be fantastic only if the present frontier-situation between spirit and Nature in each human being were so intelligible and self-explanatory that we just “saw” it to be the only one that could ever have existed.
My books address this very “frontier-situation between spirit and Nature”, proposing a bidirectional dualist interaction between the Mind of God through His Holy Spirit and the mind and soul of Man through neural synaptic networks.