That's, of course, what makes it a paradox - an example of the limits of logic - and so much fun, and so frustrating, at the same time. And it's the basis of Netflix's remarkable new series, The OA.
If you're reading this, you likely know the story, so there's no point in my repeating it to you in any detail again. But the gist is: Prairie runs away from home, is scooped up by today's version of a mad scientist - bent on discovering/proving there's a life or dimension after death - and holds Prairie and a bunch of other new adults in his basement, where he conducts experiments with them. He has selected them because they all have had near-death experiences. They figure out a way of harnessing forces - "movements" - that enable them to cure disease, bring people back from the dead, but not yet quite escape. But the mad scientist does set Prairie loose. She returns to her home town and her adoptive parents, and systematically puts together a new group of high school kids, plus a middle-aged vice principal, who under Prairie's tutelage, learn the moves - that is, learn how to harness some of the cross-dimensional forces that can have so much impact in our reality.
Now in the above story, here are the only things we know to be true: Prairie ran away from home ... Prairie gets back to her home town (and everything after). But everything in the three dots - or ellipsis if you want to be fancy - well, all of that may be true, or may just be a product of Prairie's super-fertile imagination.
The first season puts this question to the test, in the worst possible a way. A shooter enters the high school. Prairie's team uses their moves to ... stop him. Not by laying a finger on him. But doing what look to the uninformed like crazy gestures - but to those of us informed by what we saw in the previous seven episodes, the moves that summon the inter-dimensional forces. The result is that the shooter is frozen long enough to be tackled.
So ... does this prove that Prairie was telling the truth - that she figured out a way, in the mad scientist's basement, of summoning some kind of trans-dimensional forces? Well ... no ... because the gestures or movements to summon the forces are so bizarre, they could have distracted the shooter in the high school long enough to be tackled.
And if this crucial, penultimate, undecidable scene isn't enough, we discover that Prairie, who was rushing to the school, was shot at some point, and is rushed away in an ambulance, very badly wounded.
What does that tell us about the truth or fiction of Prairie's account? Well, if her friends at school have really mastered inter-dimensional life-and-death powers, and can get themselves to the hospital, they can bring her back to life if she died, and/or to full health is she was only badly wounded. If not - if Prairie and those people at school are only kidding themselves, then Prairie will die. And that's exactly where this first season ends.
Since this a television series, and now a very successful one at that - well, your guess is as good as mine. On the other hand, if there is no second series, then, well, Prairie's new friends and we the audience were just brilliantly lied to.
more alternate dimensions here