I'm absolutely obsessed with the problem. I've seen many people dismiss it, and I've seen many arguments against it, none of which seem to cut the logical mustard. The problem for me boils down to "world-having". If something shows up in my world, I want to know if there is a way to determine if there is any kind of world connected to it, or if it is merely an object in my world. 

But worlds seem necessarily exclusive and necessarily private (for even if you were to jump into the mind of another, then your previous body would be reduced to a representation in the new world - at any rate, it seems that only one mind can exist at a time). Any attempt by another to demonstrate the existence of their own world would necessarily be through means of a representation, which could just as well be copied by a mere object (philosophical zombie).

Even if we allow other experiences/minds/worlds to exist in an offhand way (like we might allow objects in space to exist outside of a perception field for various reasons, contra-Berkeley's idealism
), we cannot deny that our own experiences have a vitality and immediacy which affords them a different and *singular* quality of being.