Perhaps a most interesting question, therefore, would be: what legal fictions still exist in our legal thought and why? One comes to mind - the "renewed" motion for judgment as a matter of law after the jury verdict comes out. What logical or moral principles does this fiction serve?

I think Jesse has a point, but there is something I am hesitant about. I think there is a danger in speaking of law as something in between philosophy and religion and mathematics because it opens the door to viewing the law as a set of normative principles. To think of law as a sort of multi-disciplinary body of knowledge that is a combination of the aforementioned studies can imply that it has evolved over time through deliberate, deep thought and study. While this may (or may not) be true one case at a time, taken collectively - statutory and common law - law is hardly just a synthesis of these studies. To this end, Holmes gives the example of the way the courts treat larceny, which reflects neither logic nor morality, but the effects of (perhaps imprudent) judicial restraint and tradition.