"How do you know that?"

     The standard line that someone who uses Presuppositional Baloney uses when he is clearly defeated is to ask "how do you know that?" It is not a sincere question, and any response will be met with the same question. I think that the best thing to do when a PB'er starts that is to acknowledge that he knows he has lost, openly regard it as a concession of defeat and accept that concession.