Who goes to heaven and who does not is not absolute truth. God is absolute truth. Who goes to heaven and who does not is a matter of Gods will. I do not claim to know all things about God or what He wills. I claim to have some knowledge of God but God is far beyond what I know. He is infinite, so I can not say what His will is.
Even math though can not be absolutely certain. If you doubt truth in an absolute sense as in God and say that all people believe something different and therefore there is no truth then it is just as logical for me to say that your whole conception of reality is screwed up or for you to say the same about me. If I doubt absolute truth, then that means that all things come down to subjective opinion, even math. The only reason we say that math is conclusive is because it makes sense to us. But if you have someone who it does not make sense to then they will not say it is conclusive. That persons subjective opinion is just as valid as mine or yours or even Stephen Hawkings subjective opinion regarding math. Just because your logic and mine and Stephen Hawkings logic has led us to believe that 5 + 5 = 10 that does not actually mean that that is a true statement. What if someone comes along and says, ‘on the contrary, I say that 5 + 5 = 15.’ Who are we to say he is wrong? His subjective logic has led him to a different conclusion than our subjective logic. So math comes down to convincing all that it is true. If you do not convince all that it is true then you still have the justifiable statement that it is false.
We could also make the leap of the ultimate skeptic who says that I can’t even prove that you exist. You might just be a figment of my imagination.
So really, does it get us any where to deny absolute truth? I say no. I does not free us, it only confuses everything.