Consistency issues also arise when the NUMBER of arguments of a verb changes. The number of arguments of a logical predicate should always be the same. The number of arguments of a predicate is called its arity. The arity of a predicate should never change.
Wrong
John ate the apple. EAT(j,the apple) John ate. EAT(j) Right
John ate the apple. EAT(j,the apple) John ate. EAT(j, x)
Why
EAT(j, the apple) EAT is 2-place relation