<pedantry>
In the culture of the day (middle-east, thousands of years ago) many arguments - even little ones - would escalate, sometimes into generations-long blood feuds. The "eye for an eye" law was a law of peace! Even if someone did something incredibly painful, disfiguring, and debilitating as gouging out your eye, you weren't allowed to extract revenge on their family or property, or even to torture or kill the guy. The most you were entitled to was his eye. No more blood feuds allowed. </pedantry>