So the formation rules of predicate logic sit pretty well with me...but one thing that we don't seem to have covered explicitly is precisely whether a name or variable by itself is a wff. It doesn't seem to me intuitively that say "Superman" by itself should be a well-formed formula, but unfortunately I can't explain why this would be the case :P

I would have thought that for a name or variable to be part of a wff, it would have to be preceded by a predicate of some sort. So "Superhero(Superman)" is a wff, and "Superman" is not.

Am I right? If not, why? Thanks in advance!