MEPHASTOPHILIS.: Hell hath no limits, nor is circumscribed
In one self-place; for where we are is hell,
And where hell is, there must we ever be.
. . .
All places shall be hell that is not heaven.
FAUSTUS: Come, I think hell’s a fable.
MEPHASTOPHILISs.: Ay, think so still, till experience change thy mind.
. . .
FAUSTUS: Think’st thou that Faustus is so fond to imagine
That after this life there is any pain?
Tush, these are trifles and mere old wives’ tales.
(5.120135)

This exchange again shows Mephastophilis warning Faustus about the horrors of hell. This time, though, their exchange is less significant for what Mephastophilis says about hell than for Faustus’s response to him. Why anyone would make a pact with the devil is one of the most vexing questions surrounding Doctor Faustus, and here we see part of Marlowe’s explanation. We are constantly given indications that Faustus doesn’t really understand what he is doing. He is a secular Renaissance man, so disdainful of traditional religion that he believes hell to be a “fable” even when he is conversing with a devil. Of course, such a belief is difficult to maintain when one is trafficking in the supernatural, but Faustus has a fallback position. Faustus takes Mephastophilis’s assertion that hell will be “[a]ll places … that is not heaven” to mean that hell will just be a continuation of life on earth. He fails to understand the difference between him and Mephastophilis: unlike Mephastophilis, who has lost heaven permanently, Faustus, despite his pact with Lucifer, is not yet damned and still has the possibility of repentance. He cannot yet understand the torture against which Mephastophilis warns him, and imagines, fatally, that he already knows the worst of what hell will be.