I'm looking for a word to describe something that seems overwhelmingly likely to be true but that we aren't sure whether it is or not. For example "everyone will die". It seems very unlikely that there will ever be anyone who will never die since life is so fragile, but we don't know that with 100% certainty, so I would not feel well saying "The fact that everyone will die someday concerns me". Alternatively if there is no word for it, how could I phrase it differetly?
I'm on my phone and the comment button doesn't work, but to answer the first comment at time of this edit: I have no proof that everyone will die. Only statistical evidence in favour of it. And I'd rather not use the word "certain" when there's a chance of it not happening, since people might interpret it wrong. I'd rather have a clearer and less ambiguous wording.