Editing Proximate cause (section)

==But-for test==
A few circumstances exist where the '''"but for" test''' is complicated, or the test is ineffective. The primary examples are:
* '''Concurrent causes'''. Where two separate acts of negligence combine to cause an injury to a third party, each actor is liable. For example, a [[construction worker]] negligently leaves the cover off a [[manhole]], and a careless [[Driving|driver]] negligently clips a [[pedestrian]], forcing the pedestrian to fall into the open manhole. Both the construction worker and the careless driver are equally liable for the injury to the pedestrian. This example obeys the '''but for test'''. The injury could have been avoided by the elimination of either act of negligence, thus each is a '''but for''' cause of the injury.
*'''Sufficient combined causes'''. Where an injury results from two separate acts of negligence, either of which would have been sufficient to cause the injury, both actors are liable. For example, two campers in different parts of the woods negligently leave their [[campfire]]s unattended. A [[Wildfire|forest fire]] results, but the same amount of property damage would have resulted from either fire. Both campers are equally liable for all damage. A famous case establishing this principle in the United States is ''Corey v. Havener.''<ref>''Corey v. Havener'', 182 Mass. 250.</ref>
*In the United States, the rule of '''''[[Summers v. Tice]]''''' holds that where two parties have acted negligently, but only one causes an injury to a third party, the burden shifts to the negligent parties to prove that they were ''not'' the cause of the injury. In that case, two hunters negligently fired their [[shotgun]]s in the direction of their guide, and a [[Lead shot|pellet]] lodged in his eye. Because it was impossible to tell which hunter fired the shot that caused the injury, the court held both hunters liable.<ref>''Summers v. Tice'', 199 P.2d 1 (Cal. 1948).</ref>
*'''Market share evidence'''.<ref>See ''[[Sindell v. Abbott Labs]]''.</ref> Injury or illness is occasioned by a [[Fungibility|fungible]] product made by all the manufacturers joined in a lawsuit. The injury or illness is due to a design hazard, with each having been found to have sold the same type of product in a manner that made it unreasonably dangerous, there is inability to identify the specific manufacturer of the product or products that brought about the Plaintiff's injury or illness and there are enough manufacturers of the fungible product joined in the lawsuit, to represent a substantial share of the market. Any [[damages]] would then be divided according to the market share ratio.

Since but-for causation is very easy to show and does not assign [[culpability]] (but for the rain, you would not have crashed your car{{spaced ndash}}the rain is not morally or legally culpable but still constitutes a cause), there is a second test used to determine if an action is close enough to a harm in a "chain of events" to be a legally culpable cause of the harm. This test is called proximate cause, from the Latin ''causa proxima.''