In order to unite his theories about the soul .
How soul operated within the body , he adapted the theory of the pneuma , which he used to explain how the soul operated within its assigned organs , and how those organs , in turn , interacted together .
In order to unite his theories about the soul and how it operated within the body , he adapted the theory of the pneuma , which he used to explain how the soul operated within its assigned organs , and how those organs , in turn , interacted together .