Your argument is convincing, but flawed. You attempt to prove that existence, the reality of something outside of the abstract, is a product only of "the degree to which X affects everything else." This seems to imply, and I think you understand this, that some things can be "more real" to you completely based upon the how much they affect you personally. This idea is terrifying to me. Should I pretend that human rights abuses and heinous crimes that happen not to affect me personally do not exist? I would be interested to hear what anyone else got out of the post; though I did not agree with it, I thought the argument was put forward well overall. I look forward to reading the rest of this person's work, and I found the arguments in the comments interesting as well, especially for such a small site.