Not so much wrong as futile. You can argue for the existence of unicorns: one-horned cattle or antelopes can occur as a mutation, and that mutation could become stabilised. But it hasn't. Similarly, you could argue for the implausibility of a platypus, but you'd be wrong. Existence and non-existence cannot be proved by theoretical arguments.
Yes and no. A concept can be proven impossible if it's internally inconsistent. It's just that internal consistency isn't a guarantee of external experiences.
So an "experience of a headache" is the experience of a set of sensations that the person attributes to a ...?
The term "headache" doesn't speak to attribution.
It's a basic principle of epistemology that experiences are accepted unless there is clear evidence that they are wrong. The experience of seeing a snake is an experience of seeing a snake, unless you pick it up and find it's a toy or a length of rope.
That seems like a pretty crappy and unreliable principle: "if you assume it's true, it must be true unless we can confirm it's not?" This seems like a principle invented by someone who had no idea that human beings make mistakes all the time and not a "basic principle of epistemology" at all.
How do you make that out? Religious experiences are hardly rare and often have considerable impact.
I was talking about the platypus: here in North America, they're rare and irrelevant to people's daily lives. My life in a world where platypi are fictional would be the same in every measurable way to a world where they're real. The literal existence of platypi has no tangible impact on my life.
OTOH, if we were talking about whether, say, house cats were fictional, that would be a different story. I live with two house cats. If cats were fictional, my life would be measurably different every single day.
Is your god more like a platypus - i.e. irrelevant to our day-to-day lives - or like a house cat - i.e. is completely intertwined in our lives?
And we're talking about gods, not religious experiences. If you want to argue that religious experiences imply the existence of gods, then you're going to have quite a bit of work to do.