The overwhelming majority of the human population disagrees with you. Yes, rationally, we know with great certainty there is no afterlife. (well, at least we know with almost the same certainty that there is no flying spaghetti monster, the p value of each possibility is infitesmally smaller than 1)

But we choose to accept unverified statements from our elders regarding the afterlife rather than dwell on the facts of death and fail to procreate.