Moving the goalposts is a logical fallacy that takes the following form. 1. * 1st person, "Prove A to me!" 2. * 2nd person, "This proves A." 3. * 1st person, "That's not good enough, you've got to prove B as well!" 4. * 2nd person, "This proves B." 5. * 1st person, "That's not good enough, you've got to prove C as well!" 6. * 2nd person, "This proves C." 7. * 1st person, "That's not good enough, you've got to prove D E & F as well!" And so it goes on, however much you prove if your opponent keeps moving the goalposts there's always more you haven't proved yet.