In article <firstname.lastname@example.org>, WM <email@example.com> wrote:
> On 9 Dez., 00:58, Virgil <vir...@ligriv.com> wrote: > > > A mathematical set only has to distinguish between elements and > > non-elements, never between one of its element and another. > > A real number in mathematics has to be an individual that is distinct > from every other real number.
But no criterion for being in, or not in, the set of reals distinguishes between any one real and any another real.
So however relevant such differences may be for other purposes, as far as any set containing them is concerned differences between members is totally irrelevant.
"Is x a member of y?" is a purely yes or no question. --