Date: Apr 9, 2013 10:03 AM
Author: Aatu Koskensilta
Subject: Re: Naive set theory

Zuhair <> writes:

> What's the proof of the following in naive set theory?
> Not exist x. x is empty

By Russell's paradox, there exists a set R such that R in R and R not
in R. By ex falso quodlibet, there is no set with no elements.

Aatu Koskensilta (

"Wovon man nicht sprechen kann, darĂ¼ber muss man schweigen"
- Ludwig Wittgenstein, Tractatus Logico-Philosophicus