I think that we're possibly all simultaneous reincarnations of each other, and all a reincarnation of every life that's ever been lived. But, our minds shape past life regressions so that they're relevant to something that's going on in our present life.
So, it isn't so much that dozens of people walking around right now probably believe that they were Joan of Arc in a past life, even though Stan Gooch wrote a book The Origins of Psychic Phenomena that studied the historical error of Joan of Arc's date of death. It is, for me, the relevance of why does the person who is doing the regression, why do they subconsciously relate to this historical figure? Maybe, like Joan of Arc, they feel like they're being persecuted for something that they believe is right. That's one example. That's why I wouldn't go, "Oh, but past life regressions are so fake and fluff!" Because if that's the way that people can express themselves, then I don't believe that the belief itself should be entirely shut down. I'm just saying that it can be interpreted differently than a literal truth.