How do you chase after what you do not know existed?

This case is in what i studied in NUS,Reasons and persuasion.
The case discusses about whether virtue is teachable or is it not.The story goes like this.
Learning is a recollection of what you studied in your previous life,as in when you are in hell or the life before this life.
Like what is in the book,

Persephone will accept requital for ancient sin from those
Whose souls she will restore again to the sun above in the ninth year,
And from thse seeds men will grow,
Noble kings ,mighty in strength and greatest in wisdom,
And for the rest of time men will call them sacred heroes.

WHat it means are soul is immortal,gets reborn from time to time,after death,after life.So there is no wonder a soul can recollect all it has studied previously in life.
If you are smart in previous life,then you are smart this life.
I dont really agree with this philosophy if that's the case.If everyone can recollect all everyone has studied in previous life,then there will be no 'not that smart people' in this world.How can the book state something which is so out of the world?If the author has recollected what he has learned ,then he shouldnt write these things down.AM i right?