>It is irrational to believe something is true or possible unless you have evidence for it.
If you have no evidence against it, it is not irrational to believe something is possible.
If you have no evidence against it, it is not irrational to believe something is possible.
If I claim there are tiny, sentient gnomes running around in my garden, I should have some evidence for that claim. If I insist it's possible without identifying any evidence, you would rightly conclude I'm insane.
You evaluation of evidence, or your logical process, could both be mistaken and so you might believe things that are not true. But if your belief is based on evidence, you can test it and revise your understanding.