I think the meaning of the word 'argument' in the "joke" fits one or more of these:
. 4. Logic. The minor premise in a syllogism. 5. Mathematics. The independent variable of a function. The amplitude of a complex number. 6. Computer Science. A value used to evaluate a procedure or subroutine
---------------------------------------------------------
Excerpted from American Heritage Talking Dictionary
Copyright © 1997 The Learning Company, Inc. All Rights Reserved.
.bh
.