Mathematics only tells you answers to questions in the real world after you have taken the one vital step of choosing which kind of mathemat ics to apply. Even if there were a rival number theory which used the symbols '2', '3', and '+ ', and in which a theorem said "2 + 2 = 3", there would be little reason for bankers to choose to use that theory! For that theory does not fit the way money works. You fit your mathematics to the world, and not the other way around. For instance, we don't apply number theory to cloud systems, because the very concept of whole numbers hardly fits. There can be one cloud and another cloud, and they willcome together and instead of there being two clouds, there will still only be one. This doesn't prove that 1 plus 1 equals 1; it just proves that our number- theoretical concept of "one" is not applicable in its full power to cloud- counting.