How do you know you won't eventually be somebody else after death?

 The below post is an answer I gave to a question asked of me on the site "Quora." I have republished it here. You can find the original answer at: https://www.quora.com/profile/Parker-Zurbuch/answers 

Original Question: How do you know you won't eventually be somebody else after death?

You don’t know with 100% certainty. You cannot know anything with 100% certainty; BUT, you can gather up the most rational evidence, and make a “most logical conclusion” from said evidence.

As for becoming someone else after death, the only rational way I think you could deduce such a claim as being “most logical” would be to look at evidence of those who have claimed positively for the reality of reincarnation.

This is similar to the question “Do angels exist?.” You cannot know 100% either way, but you can look at all the evidence — however, with the question of angels (as with reincarnation), the evidence for these things depend on other premises. You cannot have angels unless there is a spiritual dimension to reality. If there is a spiritual dimension to reality, are concepts (such as truth, goodness, beauty) parts of reality instead of just parts of man’s imagination? So on and so forth.

Likewise, you cannot have reincarnation unless there is a spiritual dimension to reality: some sort of consciousness that can “jump” from one body to another between death and life.

Reincarnation has some other ideas going against it which must be considered, such as, “If you are reincarnated, why don’t you remember your previous life (lives)?” or, “If you claim to remember your previous lives, and claim to be reincarnated…how can you prove this?”

One should never believe something just because someone says so. This leads to disaster. To live a fulfilled life, one must have a basis for one’s beliefs. Some sort of solid rationale. But one must always beware of creating a logical system based on false premises. A system can be logical, but if based at a false starting point, it cannot be rational and cannot be reality. I am not assuming the questioner has such faulty assumptions, but am rather cautioning against them because they are easy to fall prey to for anyone, myself included.

I do not see how one could have a logical system for reincarnation based on valid premises; unless there was some sort of spiritual or religious system which fit reincarnation into the wider view of reality. Such a spiritual or religious system would need to also be non-contradictory in its claims. Its followers wouldn’t need to adhere to the religious system perfectly, but the system itself would need to be logically coherent, and have valid premises for reincarnation to be considered a feasible aspect of reality.

EDIT: When I say a “religious system” I do not mean that in the strict sense, but more as a “larger system in which the concept of reincarnation could fit.” To me, it seems that the concept of reincarnation cannot hold itself up by its own bootstraps — it needs other ideas for it to be based on. This is what I mean by a “religious” or “rational” system.