User blog comment:Emlightened/BIG FOOT is SMALLER than FISH NUMBER 7/@comment-5529393-20161225093559/@comment-1605058-20161225113245

"[...]in which case you don't actually get a truth predicate for \(V\)" Indeed we don't. But we don't need to - as long as we get a truth predicate for parameter-free formulas, we can talk about definability of numbers (since we define them without the use of parameters in Rayo's function) and hence also about the Rayo's function.