No, I don't.  What makes this any different to 'reincarnation'?  How could they 'refine' themselves without coming back as someone else - something that my 'one soul, one individual' understanding rules out?

You say you don't believe a person who does bad stuff can ever change, that they should be punished endlessly and they can't learn to do otherwise?

That is strange given that each of us has done bad stuff and can often feel guilty about causing hurt to others, so much so that we mend our ways and try to be better people. The refinement can start right here on Earth. You hear of criminals who have turned their lives around completely.  Eternal Progression is open to every human soul.  Some might come back here (reincarnation) or might continue to progress in the spirit realms, depending on what lessons need to be learnt. Again we have done reincarnation as a topic and there are different understandings to what this means, plus lots of accounts on the web.

reincarnation info

And now I am probably going to confuse you more by adding this ...

The larger soul never incarnates in its entirety in matter. That portion of which you are aware in an earthly body is only a splinter and not the whole.

If you want to know a bit more then do a search on Silver Birch.