So if a family member starts believing they will give birth to puppies, you will instantly give that credibility? How does this follow when irrationality is cle

So if a family member starts believing they will give birth to puppies, you will instantly give that credibility? How does this follow when irrationality is clearly at an extreme? And what if your father believes in UFOs and your mother doesn't? There's something more than just giving credence due to authority, especially in these extreme circumstances.