The preceding questions should have got you thinking a bit about the area of law known as negligence . In the legal world, negligence is simply careless behaviour on the part of one person that causes injury or suffering to another person. Of course, right away the question arises as to what is and what isn't careless behaviour. Was the owner of the well Carlos fell into careless in letting the wood rot? 

Here's another situation to think about. This actual event went to court:

A group of people were playing cricket. One of the players hit the ball over a wall surrounding the cricket field onto an adjoining side street where it struck a passer-by, the  plaintiff  in this case. The passer-by sued the cricket players (who thereby became the  defendant in this case) for his injuries and argued that it was careless, or negligent, to play a cricket match under conditions whereby it was possible for a ball to be hit over the wall of the field and into the street. The evidence revealed that this had happened only five or six times in the history of the cricket field and that in the vast majority of instances, a ball could not be hit out of the cricket grounds.