 The HP-er advocates Hume’s Principle in its unrestricted form, and is thereby committed, as we have seen, to the existence of a denotation for every term of the form {x | Φ(x)}. The HP-er is committed, not only to the number of all natural numbers, but also to the number of all self-identical things—or, at least, so Wright was in Wright (1983). This ‘universal number’ #x(x = x) is sometimes called ‘anti-zero’. In n. 5 on p. 187 one reads 