In law, a proximate cause is an event sufficiently related to an injury that the courts deem the event to be the cause of that injury. There are two types of causation in the law: cause-in-fact, and proximate (or legal) cause. Cause-in-fact is determined by the "but for" test: But for the action, the result would not have happened. (For example, but for running the red light, the collision would not have occurred.) The action is a necessary condition, but may not be a sufficient condition, for the resulting injury. A few circumstances exist where the but for test is ineffective (see ). Since but-for causation is very easy to show (but for stopping to tie your shoe, you would not have missed the train and would not have been mugged), a second test is used to determine if an action is close