The conjecture is reasonable. Heaven and Hell are moral extremes, the fantastical carrot and stick of religion wielded to promote the moral values of Christianity. To see Borges perspective better, you have to try to comprehend the length of eternity- entire galaxies spinning into existence and dissolving away- and that just the first hour of the interminability of eternity. The idea that a human could either suffer or be rewarded for all eternity based on their actions in a very brief lifetime makes no sense, especially coming from someone with the intelligence to bring the universe into existence.

Well, tell God that when you meet him.