How can we explain Jewishness according to Philip Roth's point of view in The Defender of the Faith?
Philip Roth's point of view in The Defender of the Faith is not illustrated through Grossbart who is a vain, unscrupulous manipulator who takes advantage of labels that have no meaning for him in order to attain special treatment and privileges. Roth makes it clear by Grossbart's low and scurrilous (scurrilous: gross abusive buffoonery) behavior that Grossbart's Jewishness is as much a sham as a Chinese egg roll for a Passover Seder meal.
Roth's point of view on the truth of Jewishness is illustrated through Marx, who hits the marks when it comes to understanding that sub-divisions, so to speak, of humanity come after--not before--common humanity. For Roth, as illustrated through Marx, Jewishness puts human values before special values (e.g., Marx wants what is right "for all of us"); patriotic values before factional values (e.g., being a good soldier); being a good Jew before purely personal desires (e.g., unscrupulous privileges that violate the higher orders of values).