As a youth, I remember being fascinated by an idea that a preacher once presented. He said that in heaven, it won’t be that everyone has good behavior all the time, but that sin will be unthinkable.

How is that possible?

OK. I say to you, don’t think about elephants. What are you thinking about?

Elephants.

(From the movie Inception, but used in various forms much earlier.)

How could sin be unthinkable? By brainwashing us? That would be dehumanizing. It doesn’t seem to jive with “the knowledge of good and evil” which was arguably for mature man (though not the infantile man who grasped it unlawfully in the beginning.) I think philosophers of language may be on to something though.

Words sitting in a dictionary sit still and stale. They are the husks of meaning. Put into action, they take on life and animate. They can not do so without drinking the water of their context and breathing the air that passes through the lips of the one speaking it. In this way they change. In this way will evil be undone and Christ Jesus redeem all of creation. Even the words used to describe evil and the void – HE has the power to subvert even these and make it so that sin becomes even unthinkable. the knowledge of him will go through all the earth, hovering like the spirit did over the waters – hovering over his children warming the tiny seed in them that will grow into the new creation.

It was … declared by Aquinas that it was of the nature of God to know all possibilities, and to determine which possibility should become fact. “God would not know good things perfectly, unless He also knew evil things … for, -since evil is not of itself knowable, forasmuch as `evil is the privation of good’ as Augustine says, therefore evil can neither be defined nor known except by good.” Things which are not and never will be He knows “not by vision”, as He does all things that are, or will be, “but by simple intelligence”. It is therefore part of that knowledge that He should understand good in its deprivation, the identity of heaven in its opposite identity of hell, but without “approbation”, without calling it into being at all.

It was not so possible for man … To be as gods meant, for the Adam, to die, for to know evil, for them, was to know it not by pure intelligence but by experience.

-Charles Williams, He Came Down from Heaven, Quoted by Sayers in the preface to Ch.7 of The Mind of the Maker

I like very much how Williams puts it. God can “know” evil without bringing it into being. We, on the other hand, to know it is to give it pneuma. Without the law though, we could not articulate it. It seems that in some sense, even the law will be undone.