It's not empirically testable. Nobody has truly died and come back and no one can. Even if all religions are false it does not follow that there is absolutely nothing after clinical death.
This is just a limitation of science, because we need a conscious mind to test and/or interpret the results.
> it does not follow that there is absolutely nothing after clinical death.
Where's your evidence?
What if I claimed when you die you are reincarnated as a zebra on omnicrom-5? Why is that more or less reasonable than an explanation some religious leader made up one time when he was high?
Anyone can come up with some ungabunga, but unless you have evidence there's no rational to believe it.
The point is there is no evidence, and also there is no claim that I am making. It is unknown. The only claims of resurrections are religious in nature, which proves my point.
This is just a limitation of science, because we need a conscious mind to test and/or interpret the results.