Date: Dec 9, 2012 11:34 AM
Author: fom
Subject: Re: Mathematics in brief

On 12/9/2012 2:49 AM, Virgil wrote:
> In article
> <>,
> WM <> wrote:

>> On 9 Dez., 00:58, Virgil <> 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.

Only with respect to a well-construed universe of discourse.