Technically correct. But kind of backs every argument into a corner. I'm assuming also, anything like a paper with data, can also be questioned in the same way. Don't object, I've seen that done. So basically, don't talk about anything, because anything you say is contradicted by something somewhere. Everything is True, Everything is False, everything is subjective. There is no reality. Every person has there own point of reference that is completely subjective and invalid.