What is the main thesis of Plato's tripartite theory of the soul?
a. The soul of a human being is modeled the structure of nature itself: the mind is analogous to the heavens or the sky; the body is analogous to the earth or material substance; the soul is the invisible force that unites these two distinct realms.
b. There are three elements of life: birth, growth, and death. Only the soul can escape all three.
c. Only a well-balanced person who has their appetites and desires in check and who uses their willpower or spirit as reason commands is a wise and happy person.
d. The human soul is made of three parts: the body, the mind, and the spirit.
e. Each has an equally important role to play in the life of a virtuous person. The soul goes through three different stages of existence: first there is creation; this is followed by formation into substance structure (such as a human body); finally, there is dissolution and transcendence into eternal being.