It seems Dr. Piper is equating sleeping, here, with death, and implying that we needn't fear death because it's not real.

I used to fear death, when I believed there was an afterlife and I was plagued with doubts about whether I would be playing the harp in the clouds, or suffering eternal torture. Once I realized there isn't anything after death, I was able to understand that dying is just like not being born yet. I've already experienced that.

The only fear left, really, is the fear of a painful death. But, I have a fear of painful life, too, so I have to keep dealing with that one.

One of the five rivers of the underworld of Hades, also known as the river of unmindfulness. Everyone who drank from it experienced complete forgetfulness. The word literally means 'oblivion', and is related to the Greek for 'truth' (aletheia) which means 'unforgetfulness'. So there is some kind of connection between Lethe and concealing the truth. At the same time, if the shades in Hades didn't drink from Lethe (and thereby have their memories erased), they would never have the chance to be reincarnated.

This interpretation of Christian eschatology, based on futurism, presents a utopia is exclusive by its very nature. There isn't just the battle of good vs. evil, of Yahweh vs. Ha-satan, but also a final judgment and the annihilation of "unsaved" souls.

But like I stated previously, even modern concepts of utopian societies are exclusive in at least some, or many ways. There is something that we have to sacrifice or give up, or communities/groups that we have to exclude, in order to achieve the ideal. Then again, what is the ideal? In ancient literature the utopian society is metaphysical in nature, based largely on the concept of an afterlife. Within the context of an afterlife there is no human experience or condition, so the ideal, whatever that may be, can be achieved. If it's an afterlife, and one often depicted in Western literature, film, art, etc., then it is devoid of the trials and tribulations that make the human condition what it is, and make us what we are: imperfect.

But in the real world, outside a utopian afterlife, the human condition is alive and well. Conflict and struggles persist. There is an aspect of control earth-based utopian societies, and one could even say the classic heaven-based utopian concept is not without its own set of rules governed by Yahweh, Jesus, et al.