In the Western tradition, there are two great legal schemes that have persisted to this day: the common, or English, system, and the civil, or Roman, system. Let's take a quick look at both.
The common law system is often said to be "judge-made" law, but in fact it is not - it is based on the customs and mores of the community. A judge merely decides cases based on this understanding of "the law." A key feature of this system is that judges can decide wrongly; a judgment that falls outside this set of customs and mores can be overturned on the principle that it is "not law." Judicial precedent holds great significance out of a sense of deference to previous judges' reasoning capacity and ability to draw an accurate interpretation of what the common law is.
The civil law system seeks to be a "rational" system. Instead of the law being based on custom, it is based on a previously-agreed code. This code is intended to be gapless, covering every aspect of our legal existence. Judgments are made in this system by determining what the relevant facts are (the inquisition), and once finding those facts, seeing what aspect of the code they correspond with. From there, a determination can be made of what the law is for a given set of relevant facts. Subtle legal questions are not handled by judges, but by references to the academic study of the law, while changes are solely through legislative bodies.
Thoughts on the two systems? Which do you prefer? Do they correspond to any of the subjects we discuss on this site? Which is fairer?