[foldr]

>I know that you believe you have them, and that I believe I have them, but that doesn't mean that they have any tangible reality

It does in the case of experiences. I can't even conceive of what it would mean to be mistaken about the very fact that you are having experiences. It would be a very different sort of mistake from that of being mistaken about the _object_ of an experience (thinking that you are hearing voices when there aren't any, etc. etc.)

Also, your use of the word "tangible" is very odd in this context. Almost by definition, nothing could be more tangible than an experience.

>[I know that] I believe I have them

So, do you believe that you have them or not?