Paradox

160 A BRIEF HISTORY OF THE PARADOXpose I believe that my friend Ted drinks and you try todissuade me: “Ted has an allergy to alcohol, so since no onewith such an allergy drinks, Ted does not drink.” I amunmoved. I reveal my reasoning:1. Ted drinks.2. If Ted drinks, then if you present a valid counterargumentthat implies Ted does not drink, then thatcounterargument has a false premise.3. Therefore, if you present a valid counterargument to“Ted drinks” that implies Ted does not drink, then ithas a false premise.4. You have presented such a valid counterargument to“Ted drinks.”5. Therefore, your counterargument has a false premise.By hypothesis, I believed the first premise prior to yourcounterargument. I also fully believed the second premisebecause it is analytically true. Since the third statementfollows by modus ponens, I took this warning to heart. Byadvancing your counterargument, you make the fourthpremise obvious to me. Conjoining it with the third yieldsthe final conclusion by another modus ponens inference.This metaargument can be generalized to yield Sextus’sconclusion that no one can be rationally persuaded by adirect argument.Sextus was aware that it seems too self-defeating to arguethat nothing can be justified by argument. However, “Nothingcan be justified by argument” is not a contradiction; noris there any contradiction in “Sextus argued that nothing canbe justified by argument.” Since both these sentences areconsistent, Sextus does not feel pressure to disavow them.