In article <firstname.lastname@example.org>, WM <email@example.com> wrote:
> On 15 Jun., 16:17, stevendaryl3...@yahoo.com (Daryl McCullough) wrote: > > > In this sense, the antidiagonal of the list of all computable reals > > is definable (but not computable). > > That is nonsense. To define means to let someone know the defined. If > he knows it, then he can compute it.
There are undecidable propositions in mathematics, so if P is one of them then "x = 1 if P is true otherwise x = 0" defines an uncomputable number.