If reincarnation is real, there’s a brutally simple reason it only ever throws you forward.
If you die in 2026 and your next life begins in 1500, you arrive carrying faint memories of a world that hasn’t happened yet. You’ll act just a little differently. Maybe you’re kinder to a stranger, maybe you avoid a certain food because of a half-remembered warning. Those tiny shifts ripple forward. The child you help grows up to have descendants who alter history. The joke you tell plants an idea too early. Over time, the 2026 you remember stops being accurate, which means the version of you that came from that future couldn’t have existed. The loop eats itself.
For your memories to remain coherent, the world you enter must be one you can’t retroactively rewrite. That only works if you are born after your death. You die in 2026, you wake in 2027 or 2120 or any future where your previous timeline is sealed. You can’t be the butterfly that stomps on its own branch.