Well, that is a doozie from AB - 'you can't assume that something undetectable by human means is nothing'. What a corker. It actually removes all constraints from any investigation, since, for example, I can maintain that I am experiencing Venusian mermaids, and doncha know, they are undetectable to ordinary mortals, but my special soul-death-ray-power, can detect them, and that's the evidence for their existence. This is fun.