“If you want to see what I mean by arbitrariness of categories, check the situation of polarized politics.  The next time a Marian visits earth, try to explain to him why who those favor allowing the elimination of a fetus in the mother’s womb also oppose capital punishment.  Or try to explain to him why those who accept abortion are supposed to be favorable to high taxation but against a strong military.  Why do those who prefer sexual freedom need to be against individual economic liberty?”

The best way to prove the arbitrary character of these of these categories, and the contagion effect they produce, is to remember how frequently these clusters reverse in history.  Today’s alliance between Christian fundamentalists and the Israeli lobby would certainly seem puzzling to a nineteenth century intellectual—Christians used to be anti-Semites and Moslems were the protectors of the Jews, whom they preferred to Christians.  Libertarians used to be left-wing.  What is interesting to me as a probabilist is that some random event makes one group that initially supports an issue ally itself with another group that supports another issue, thus causing the two items to fuse and unify…until the surprise of the separation. “

from The Black Swan by Nassim Nicholas Taleb