(This is the doctrine known as epiphenomenalism.)
I.e. Since its not a separate essence but only an excressence of the body, it doesnt do anything that the body doesnt do. But this is specious by dint of inaccuracy; feet are likewise excressences of the body, yet this doesnt negate their distinct fuction of walking, which the other body parts dont do. Likewise the mind does what the feet dont.
