I think Leibniz Newton, and Dedekind are describing reality. What else can I say? Even if purgation is infinitesimally brief, it is still something, in my view.
When we accepted Christ we DIED to our old nature, our old self. Purging implies an eliminating of that which is impure, that some day, given enough time, we can become pure. We will never be rid of our old nature until we die, so it cannot be purged from us here on earth.
Our new nature does not need purification. When we die physically, our old nature is finally eliminated.
The old nature cannot be purged as it is dead. The new nature cannot be purged because it’s already pure and doesn’t need it.