The atomic formula of predicate calculus is when a predicate and special case of a subject (individual) are written together. For example, if *M* is the predicate “to be a human,” and *b* is the subject (individual) “Socrates,” then *Mb* means the assertion “Socrates is a human.” This atomic formula is phrased “b is the argument of M.” Thus, *M,* as the predicate, may be applied to any subject, and that subject is then an argument of *M.* But if *c* is the subject “Vermont,” then *Mc* is a false assertion, because Vermont is not a human. Some predicates require more than one argument, thus, you can have formulas such as *Mxy.*