http://mathoverflow.net/questions/10334/what-practical-applications-does-set-theory-have http://mathoverflow.net/questions/10334/what-practical-appli... You mi

http://mathoverflow.net/questions/10334/what-practical-applications-does-set-theory-have http://mathoverflow.net/questions/10334/what-practical-appli... You might enjoy: http://en.wikipedia.org/wiki/Cantor%27s_diagonal_argument http://en.wikipedia.org/wiki/Cantor%27s_diagonal_argument