my new theory.

A person is made up of three things; MIND, BODY, and SOUL.

Your mind and body can be easily explained but my theory focuses on the explanation of the soul.

Lets put aside everything and start off with the soul.
The soul is something that lives on, despite life and death. Life and Death is just a cycle... a phase, that repeats itself over and over again within the course of your soul.

SOUL + BODY = MIND

Each new life, your SOUL inhabits a BODY, which forms your MIND. Your MIND draws suppressed memories from your past life cycle while learning new things in its current life. Everything you learnt see saw and done, is automatically recorded in your SOUL.

Think of it as a hard drive. Theres a limit to how much information your MIND can hold but there isn't to your SOUL. Your SOUL can hold an infinite amount of information. That's why it is easy to put information in, but hard to take out, as you are trying to take out a specific file from an infinite space. But your MIND will get full eventually and you have to delete files to create room, and so you forget things. But these things are still stored within your SOUL, and with time and luck, you can take this information back out from your SOUL and store it back into your MIND.

Due to this, events from your past life can indirectly affect your current one. Although your MIND has no memories from your past life, it is still stored within your SOUL. And through unexpected situations, a person maybe able to accidentally tap into their SOUL and take out a random memory or emotion.

For example a person maybe afraid of swimming even though they never had any accident or trauma with it before. They just... don't want to go near it. This could be because that this person was drowned in their past life and it is stored as a strong memory in their SOUL. So strong that it somehow reaches their MIND without them knowing.

Some might say that this cannot be true as population is increasing how can the SOUL live on? Does it split and increase then? But what if there is a fixed number of SOULS in the universe? How can you say that this isn't possible?
If so, then SOULS can also come from other planets, not only Earth. The context of their memories might be different but emotions cannot differ that much as it is what makes up a society.