Ill-digested principles are, if anything, worse than ill-digested food, for the latter harms the body and there is cure for it, whereas the former ruins the soul and there is no cure for it.
There are people who are born and die and never once are aware of their breath going in and out of their body. That's how far away they live from themselves
The soul is something which contains the body. The body doesn't contain the soul. The soul, if we put it into modern language, is the entire complex of relationships in whose context this organism exists.