Reincarnation is another "late arriving belief" tossed upon people for control. According to the late Professor Leopold Fischer:
In its present form, the way people talk about it today, it is quite
old, but it's not as old as people hope it would be. You have only a
vestigial or marginal mention of something like transmigration in the older
sections of the Veda. There is the first complete mention, though very
brief, in the Brihadaranyaka Upanishad, which is quite old. But the real
assumptions having to do with reincarnation come in the Puranic age, at
the time that the Puranas were composed, and then of course, through
Buddhism. So you might say that it reached a state of common acceptance,
I would think, around 300 B.C., but not earlier. So it is old, but in its
highly articulated form it is not so old — and the way it's talked about
now, that's recent; that's "Theosophical Society."
.......
What was in the "earlier" text?
Brihadaranyaka Upanishad:
"Upon reaching the moon, they become food. There the gods enjoy them,
just as the priests enjoy the drink of Soma watching the moon wax and
wane. When that ends they enter into space, from space into air, from air
into rain, from rain into the earth. Then they are again offered in the fire of
man, and from there into the fire of a woman so that they can go again to
the other worlds. Thus, they keep rotating."
......
If reincarnation was correct, it would have been talked about when writing began ... but ... nothing.
So, what about alleged memories of past lives? This could be anything from endogenous DMT to paranormal intrusions. There IS a "spiritual" world ... and just TONS of attempted "explanations."