Eternal Punishment is merely a form of speech for what is really Eternal Retrogression.

For as there is a Forward, so there must be a Backward.
The electric germ of the Soul--delicate, fiery, and imperishable as it is--can be forced by its companion Will to take refuge in a lower form of material existence, dependent on the body it first inhabits.

For instance, a man who is obstinate in pursuing ACTIVE EVIL can so retrograde the progress of any spiritual life within him, that it shall lack the power to escape, as it might do, from merely lymphatic and listless temperaments, to seek some other chance of development, but shall sink into the form of quadrupeds, birds, and other creatures dominated by purely physical needs.

But there is one thing it can never escape from--MEMORY.

And in that faculty is constituted Hell.