Algebraic reals are the easy part, as are the few familiar classes of transcendentals that include numbers like pi and e. There’s only countably many of those.

Algebraic reals are the easy part, as are the few familiar classes of transcendentals that include numbers like pi and e. There’s only countably many of those. The set of all reals that can be described is countable. It’s the literally undescribable ones that are the problem, ontologically speaking