Why does Socrates spend so much effort defining and describing the soul in so much detail in the Phaedrus? He tells us outright, in the dialogue. It is because no man can gain true knowledge from a speech, if the orator does not himself know how his speech is going to guide the soul to its first memory of the unified reality of beauty, found in the divine realm. Dialectic is the way to wisdom, and dialectic can only be achieved through speech.
In The Phaedrus, Plato offers up two rapturously beautiful visions of the soul of man. The first, is the Manichaean winged being of pure beauty, trapped against its will in a prison of corporeal form, and able to find relief only in the apprehension and achievement of true love. The second is a famous metaphor who’s hold on the modern mind is as ubiquitous as it is distorted and tragic.