"I think that everyone is Nathaniel"

In building on Clevinger’s accusation that he thinks he’s God, Yossarian is likely saying he sees everyone around him as “Nathaniel,” identified as one of the Twelve Apostles in the Gospel of John (although other gospel accounts refer to the character as “Bartholomew”). It comes from the Hebrew name Netanel, which means “God has given,” from natan (“has given”) and el (“God”). Of course Yossarian instantly pretends not to know or understand the name in his next remark because he’s playing with Clevinger’s head.