@MasterBeth I was just using aliens saying 'gotcha' as in, imagine they admitted we were a petri dish of experiments started 3,000 years ago and everything in our history up until then had been a hoax. It wouldn't disprove evolution but it would create new hypothesis / theories.
Just being as outlandish as you pulling Santa Clause out 
Anyhoo.
That’s why I’ve asked people for the good evidence they have for the existence of the extraordinary things (like the existence of a soul beyond the body or their constant rebirth and past lives) which they claim or suspect exist and which, if they did exist, would run counter to all our current understanding of the universe.
I'm not sure anyone ever claimed to have evidence they were hiding away from you? The thread is literally titled "do you believe"
Some posters (including me!) said what made them / makes them believe that it's possible. Or might be possible.
I have no evidence in the existence of a soul, but neither do you have evidence that it doesn't exist? Unless science has suddenly produced something concrete since the last time I read up - in which case, I'm open to believing that too.
But I'm not sure what you mean by "would run counter to all our current understanding of the universe"?
And I'm not sure we could ever debate it here because there's too much and too many theories. But.
We don't actually understand the universe? Or rather, we don't currently agree on an understanding of the universe. We haven't agreed on how or why it started. We don't know how life started. Have scientists even agreed exactly what life is yet? Nope. How are we conscious? Why are we conscious? If we are just a brain functioning as a coded computer, with inputs, processes, outputs, why are we experiencing it, and the computer, as far as we know, isn't? Because we're alive? Define being alive? They can't.
If you take one of those questions, how did life start? Reproduction first theory? Metabolism first theory? Compartmentalisation first? A combination of two? Everything first? But then you are hypothesising that the chicken and the egg happened at exactly the same, in exactly the same place, with exactly the materials needed to create the chicken and the egg.
What are the chances? When you think about that exact "life" recipe in the relation to the massive chain that started who knows how long before the big bang... it's hardly preposterous to think that other theories might have merit?
When you get into entanglement, the theory that reality isn't particles and strings but instead the entire universe, the 'many worlds' theory... and then the theory on top of them all - that they're actually just different ways of perceiving exactly the same thing. The person observing would see many worlds, but what's actually happening is quantum monism. So there is a theory in scientific existence that you can look outside your window and perceive that nothing is connected, but actually it's all connected. You are just perceiving that it isn't, because we are human and we can't actually perceive all that much of what exists.
So when someone says 'show me the evidence that a soul can jump bodies into another life'... how when we can't perceive it, and nobody is really claiming we can? How can a scientific theory exist that everything outside your window is connected, but to theorise that humans might be connected in ways we don't understand "runs counter to our understanding of the universe".
If they can theorise that the everything needed to make the chicken, the egg, and the nest got together in a shallow pond with the exact metals needed to create life brought to us by a meteorite from a universe we don't understand, then a bunch of mumsnetters can theorise about souls.
This was a fairly 'lighthearted' thread on what people believe and somehow I've got into trying to explain quantum theory that even quantum theorists don't understand... but that's why I felt the need to reply -- we don't really understand that much of anything in relation to the universe! And we might never, because how can humans ever comprehend that much?
I cannot see how this belief harms you or anyone else in any way, so what is your problem?