 So \(y\) and \(\phi\) are called “real” variables in ∗10·1 not only because they are free but also because they can range over any type. Whitehead and Russell frequently say that real variables are taken to ambiguously denote “any” of their instances, while bound variables (which also ambiguously denote) range over “all” of their instances (within a legitimate totality, i.e. type).