negligence. Likely defendant negligence was responsible and plaintiff was not cause. Causation Causation is typically a bigger issue in negligence cases than intentional torts. However, as mentioned previously, it is an element of any tort. The defendant's act must be an actual cause and a proximate cause of the result in a particular cause of action. Actual cause Actual cause has historically been determined by the "but for" test. If the result would not have occurred but for the defendant's act, the act is an actual cause of the result. Several other tests have been created to supplement this general rule, however, especially to deal with cases in which the plaintiff suffers great harm, yet because multiple acts by multiple defendants, the but for test is unhelpful. This situation occurred in the famous case of Summers v. Tice. For example, Dan and Dave both negligently fire their shotguns at Paula. Paula is struck by only one pellet and it is impossible to determine which gun it was fired from. Using the but for test alone, Dan and Dave can both escape liability. Dan can say that but for his own negligence, Paula still might have suffered the same harm. Dave can make the same argument. As a matter of public policy, most courts will nonetheless hold Dan and Dave jointly and severally liable. The act of each defendant is therefore said to be an actual cause, even if this is a fiction. A similar situation arises when it is impossible to show that the defendant(s) was/were negligent at all. This almost inevitably arises in cases also involving res ipsa loquitor. See Ybarra v. Spangard. For example, making the facts of that case more extreme, Paula goes to the hospital for an appendectomy. She wakes up, and finds her left arm has also been amputated for no apparent reason. (Note that this would implicate multiple issues and other causes of action than negligence.) For purposes of actual cause, unless there is evidence or an admission of negligent conduct, Paula will be unable to show an actual cause. In this situation too, most courts will hold all the defendants that Paula names (possibly everyone on the medical staff that was in the room during her surgery) jointly and severally liable. The act of each defendant is likewise said to be an actual cause, even if this is a fiction. Substantial factor test