system
A chat on 4chan
human
YOur brain emits emf. Your memorys have unique EMF signautre.

EMF waves either crossover eachother like nothing has happened or meet the same frequency as another wave and cancel out (thus the memory EMF journey ending).

EMFs go on forever, or get absorbed.

Embryos are extremely sensitive to EMF, this is common knowledge for the telecomm world and the WHO. 

Depending on how you lived your life, this shapes your EMF signature when you die or frequency as an example. 

When you die your memory EMF, either is absorbed by something matching your EMF. i.e. a fish egg and your memory lives on through a fish. That is, you had a life where you never belonged and wanted to be free. Matchs that frequency. If not your EMF goes on and on until it macthes the right embryo. Could be human again, if you loved your life very much. 

EMF signatures range massively. You could end up living in the same area, or an area, where your loved ones can be together. 

You may not remember past lives, but you will feel that current life to be perfect.
gpt
Bro embryos just absorb emf signatures. But yeah our memories are definitely permanently recorded, the book of life is a hard concept to ignore.