Why must the soul interact with the body? I don't believe it does. Like I said before, souls are not material. Impressions left on atoms are material. So you should be able to provide material evidence whereas there is no expectation of material evidence for the incorporeal.
Then the soul has no purpose.
If it can't interact with your body, your brain, then how can it convey the information that makes you who you are? If it can't interact with the body how can it be the animating force of the spark of life that people believe it to be?
The soul must be able to at the very minimum receive and store the information that makes you who you are so that upon death it can carry that information to the spirit world you say exists somewhere to do that it must interact with the matter that makes up your body.
Everything that is living—plants, animals, humans—has a soul and lives because of a soul. The soul is what makes a thing a living being.
www.catholic.com
The Catholic Church states:
A soul is a form that makes a living thing the kind of living thing it is—a plant, an animal, a human person. It’s “
the organizational pattern or form of all the parts and all the parts of all the parts,” coordinating the matter to be the kind of living thing it is. The soul of a plant informs and makes the plant’s matter that of a plant. The soul of a lion informs and makes the lion’s matter that of a lion.
The soul of a human being informs and makes the human’s matter that of a human being.
. Aquinas follows Aristotle on this (ST I:76:1). The
Catechism even adopts this explanation, enshrining it in official Catholic teaching:
The unity of soul and body is so profound that one has to consider the soul to be the “form” of the body: i.e., it is because of its spiritual soul that the body made of matter becomes a living, human body (365).
It seems to me that the Catholic church believes the soul interacts with the matter of the body.