the-best
Explanation
The Joke
A person arrives in Heaven and excitedly declares, "I made it! I made it to Heaven!" He then asks God about all the amazing things he can now do. God responds with genuine enthusiasm: "You can design new systems of mathematics! You can attempt to create self-consistent physical theories! Best of all, you can try to model reality using the simplest possible constructions!" The man is stunned -- Heaven turns out to be an eternity of doing math and theoretical physics. He protests, "But that sounds like graduate school!" only to be shushed by the other souls who are eagerly working away, one of them whispering, "He hears everything."
The comic plays on the idea that a mathematician's or physicist's idea of paradise would be an eternity of pure intellectual exploration -- and that this would be most people's idea of hell. God is portrayed as essentially a math professor who has designed Heaven as an infinite research university, and the residents are so devoted to their work (or so afraid of the boss) that they shush anyone who complains.
The Humor
The humor comes from the bait-and-switch of heavenly rewards. Instead of clouds, harps, and eternal bliss, Heaven is an endless academic seminar. The man's horrified realization that he has been admitted to eternal graduate school is funny on its own, but the final panel elevates it: the other souls shushing him with "He hears everything" implies that God is essentially a tyrannical thesis advisor you can never escape. For anyone who has been through academia, this is both a very specific and very relatable nightmare dressed up as paradise.