I wouldn't say it's a fool's deduction. I'd say that the only deductions one can possibly make are the ones you have the information and evidence necessary to make. You're right in that I don't know what it's like to be dead, but presumably when I am dead, I won't exactly be able to gather or use any information on the experience. And it's twice as impossible to get any experience with it here.

I can adjust my theories to match the information I have to work with, when and if I get any more. But until then, isn't it logical enough to base my conclusions on what I do know? Your argument kind of seems to be that if the possibility of my not knowing something well enough to rule it out exists, then drawing any kind of conclusions is foolish because they might be wrong. But then what's the solution? To decide that unless I know everything, I can never know anything?

I wonder if you're not projecting an immortal's perspective onto me. I'm human. I'll never know everything, never have all possible information at my disposal. There will always be things outside my experience and understanding. So the best I'll ever be able to do is draw my conclusions based on the best information I have in the moment, and act on them accordingly. Otherwise I'd just be perpetually doubting my own perceptions, and would never have enough certainty to do or believe anything. I only have the one lifetime, and I can't spend it paralyzed.

That said, I don't attempt to explain ghost pokémon. But frankly, if I did, I'd consider them separate enough from humans that I wouldn't feel as though anything that applies to them and how they work necessarily applies to us.