In Gross, the Supreme Court made important choices about causation. But, it did so without explicitly recognizing that any choices were made. This post explains the critical difference between “but for” cause and substantial factor cause. In the next post, I will explain what the choice between the two means for the ADEA.
Before starting this discussion, it is important to remember that when lawyers discuss causation in a general sense, they are usually thinking about causation as an element of a negligence claim. Since the courts largely think of disparate treatment claims as requiring some form of intent, a negligence paradigm provides an uneasy fit for discrimination law. In intentional torts, causation plays a less prominent role than it does in negligence cases. The Restatement (Second) of Torts notes that while causation plays a role in intentional torts, it works differently in that context. (§ 430, note e).
Causation is a general concept that links a defendant’s wrongful conduct to the harm caused to the plaintiff. An example is helpful. If a man walks outside his house and starts indiscriminately throwing large rocks down the street, he is acting in a careless way. However, his actions will not result in legal liability for negligence unless his careless rock throwing can be connected to harm to a person or property. For example, if one of the rocks hits the neighbor’s car, liability will result. In this case, there is the proper connection between the wrongful conduct and the harm to the neighbor. This connection is what the law calls causation.
Tort law often breaks causation into two components: factual cause and legal cause (also called proximate cause). The terminology sometimes gets confusing because it is not consistently used to mean the same thing. In this post, we are talking about factual cause. If something is a factual cause it means that it affected the outcome in some way.
Let’s go back to the rock-throwing example. Assume a man is throwing rocks out onto the street. A driver drives a car down the same street while texting. The driver becomes distracted by the texts and hits the neighbor’s mailbox. The driver does not see the rocks. In this scenario, the rock thrower does not face any liability for the damage to the neighbor’s mailbox. Even though he was throwing rocks into the street, it was the driver’s carelessness, and not the rock throwing, that caused the damaged mailbox.
In negligence cases, two standards can be used to determine factual cause. The most common standard is the “but for” cause standard. A person’s conduct is not the “but for” cause of an outcome if the same outcome would have happened absent that conduct. The Restatement (Second) of Torts provides an example of a company that does not put required lifeboats on a ship. A sailor goes overboard during the voyage during a storm. The storm was so severe that no lifeboats could have been launched to save the sailor, and the sailor is lost at sea. Even though the failure to provide the lifeboats was careless, it was not the “but for” cause of the harm to the sailor.
Negligence law recognizes that “but for” cause does not make sense in some circumstances. In these kinds of cases, two forces are operating at the same time and either alone could cause the harm. The example commonly given to illustrate this concept involves two separate fires. Imagine that a homeowner is careless in burning leaves in his yard. The fire gets out of control and starts to burn a wooded area nearby. On the opposite side of the wooded area, a camper is careless about a campfire. The campfire gets out of control and starts to burn the wooded area. In the middle of the wooded area is a house. Both fires converge on the house and destroy it.
In this example, if we use “but for” cause, neither the leaf burner nor the camper would be liable for the damage to the burned home. If the homeowner sues the person burning leaves, he will argue he was not the “but for” cause of the damage. The damage still would have occurred even without his carelessness. The campfire would have burned the house down. If the homeowner sues the camper, she will argue that she cannot be held liable because she is not the “but for” cause of the damage. The damage still would have occurred without her carelessness. The fire started by the burning leaves would have caused the damage.
In these cases, it is not fair to let both careless fire starters off the hook. However, this is the answer we would get if we applied “but for” cause. In such situations, the law allows the defendant to be held liable if his actions were a substantial factor in bringing about the harm.
In Gross, the Supreme Court chose to apply a “but for” cause standard to the ADEA. However, it failed to explain why “but for” cause was the right standard for discrimination claims.