Page "Sense and reference" Paragraph 27

Although the term " the greatest integer " has no reference in the conventional arithmetic, in the ultra-intuitionistic arithmetic suggested by Alexander Esenin-Volpin ( 1960 ), it has a reference because one of the axioms of this arithmetic is that there is " the greatest integer.

" So, in one universe, an expression can have sense without reference, while in another universe, the same expression can have both sense and reference.