> it's a reflection of an uneducated society that cannot apply common sense

The problem of common sense is that everybody has his own, you can't build rules on sand and that's what "common sense" is.

For one person it's common sense to snip bits of genital organs from infants, for the next it's common sense to pray 5 times a day, for yet an other one it's common sense to flog your children to bleeding, outright own other human beings or threaten those who don't agree with you with maiming or death. You will find people telling you it's common sense to have live grenades on your coffee tables, plant anti-personnel mines in your garden, answer a door-knock by shooting through the door or walk around with enough weaponry to take over a small country.

Relying on "common sense" is relying on hyperlocal groupthink, it's not even workable in tribal societies, it's barely workable within a small family.

Common sense is sufficient for most things. The problem with law is that what gets to court are the weird edge cases that aren't covered by common sense.

Often by the time something reaches the court, there is no possible outcome that provides justice for all, and the court instead has to determine which of the parties to screw the least.

Some things have no unequivocal decision metric. e.g. "We know it's not always fair but that's the way we have decided it goes, so everyone knows where they stand".

I think this is demonstrated by Coase's "The Problem of Social Cost" [1]

> Because in the real world there are costs of bargaining and information gathering, legal rules are justified to the extent of their ability to allocate rights to the most efficient right-bearer.

[1] http://en.wikipedia.org/wiki/The_Problem_of_Social_Cost

The satirical version of the Golden Rule that "Whoever has the gold, makes the rules." seems appropriate in this context!