They all support each other. The theory of recollection supports the theory of perpetual life by saying that everybody has knowledge from past lives, and the theory of perpetual life supports the theory of recollection because it states that the soul lives on after the body dies. The theory of perpetual life also supports the master and subject theory by saying that the human body dies but the soul moves on and doesn’t die. The master and subject theory supports the theory of perpetual life by saying that the soul is like the divine and the body is like the subject, and the divine is deathless and the subject is mortal. The master and subject theory says the the body is unintelligible and the soul is intelligible, and this supports the theory of recollection. Plato argues the immortality of souls in the Republic too, particularly in Book X. In this book, there is only one argument that stood out to me. It is that the soul can’t be fully destroyed.
“You’re right, for if the soul’s own evil and badness isn’t enough to kill and destroy it, an evil appointed for the destruction of something else will hardly kill it. Indeed, it won’t kill anything at all except the very thing it is appointed to destroy (Republic,