Proximate Cause (Scope of Responsibility) | Pam Karlan | August 29, 2013


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Proximate Cause (Scope of Responsibility)

by Pam Karlan Show/Hide

Even if you haven’t read Ray Bradbury’s short story “A Sound of Thunder,” you’ve probably heard about its central point: a time traveler, Eckels, kills a single butterfly during a prehistoric dinosaur hunt and the entire world is changed. But for his having stepped on the butterfly, the world would have been different. Travis, the hunting guide explains the idea this way:

“[S]ay we accidentally kill one mouse here. That means all the future families of this one particular mouse are destroyed, right?"
“And all the families of the families of the families of that one mouse! With a stamp of your foot, you annihilate first one, then a dozen, then a thousand, a million, a billion possible mice!”
“So they're dead,” said Eckels. “So what?”
“So what?” Travis snorted quietly. "Well, what about the foxes that'll need those mice to survive? For want of ten mice, a fox dies. For want of ten foxes a lion starves. For want of a lion, all manner of insects, vultures, infinite billions of life forms are thrown into chaos and destruction. Eventually it all boils down to this: fifty-nine million years later, a caveman, one of a dozen on the entire world, goes hunting wild boar or saber-toothed tiger for food. But you, friend, have stepped on all the tigers in that region. By stepping on one single mouse. So the caveman starves. And the caveman, please note, is not just any expendable man, no! He is an entire future nation. From his loins would have sprung ten sons. From their loins one hundred sons, and thus onward to a civilization. Destroy this one man, and you destroy a race, a people, an entire history of life. It is comparable to slaying some of Adam's grandchildren. The stomp of your foot, on one mouse, could start an earthquake, the effects of which could shake our earth and destinies down through Time, to their very foundations. With the death of that one caveman, a billion others yet unborn are throttled in the womb. Perhaps Rome never rises on its seven hills. Perhaps Europe is forever a dark forest, and only Asia waxes healthy and teeming. Step on a mouse and you crush the Pyramids. Step on a mouse and you leave your print, like a Grand Canyon, across Eternity. Queen Elizabeth might never be born, Washington might not cross the Delaware, there might never be a United States at all.”

And without a United States, you probably wouldn’t be studying Torts right now. So you see, everything is connected to everything else. Never ask for whom the bells tolls; it tolls for thee.

When should a defendant be held responsible for the downstream consequences of his actions? But for causation (that is, cause in fact) alone may not be enough. Suppose a driver – Dante – negligently backs into Priscilla’s Porsche in the Trader Joe’s parking lot, rendering the car inoperable. Pretty clearly, Dante is liable for the damage to the Porsche. And Dante might be held responsible for the income Priscilla lost because she couldn’t get to work on time. And if Priscilla had a rare piece of pottery in her trunk, Dante may (or may not) will have to pay for that too, even though most cars in a parking lot are unlikely to be carrying precious cargo. But should Dante be held responsible for the death of Tristan, a patient at Stanford Hospital because it turns out that Priscilla is a preeminent trauma surgeon and due to the delay in her arrival at the hospital because she had to wait for a taxi, Tristan was treated by a less experienced intern, maybe even an intern who made a mistake? The fender bender is a but for cause of the less expert medical care. But is it enough? And what about the loss of consortium that Tristan’s wife Isolde suffers? You can see a potentially endless stream of individuals affected.

Jonathan Zittrain captures the issue succinctly in the introduction to his playlist section : “Perhaps the best way to capture the essence of proximate cause is in a single word: fortuity. Sometimes only the barest fortuity ends up linking the other elements of negligence, and in those cases we stop to consider whether there should be liability.”

In this section of the materials, we address this issue. It’s often referred to as a question of “proximate cause” or “legal cause.” But as the “Special Note on Proximate Cause” in the Restatement (Third) of Torts: Physical and Emotional Harm explains, the term is a bit of a misnomer because the key concept is not actually whether the defendant caused the injury at issue but about whether the defendant should be held responsible. (And “proximate” only adds to the confusion because often the defendant’s link in the causal chain isn’t the closest in space or time – most “proximate” – to the injury, but we hold the defendant liable nonetheless.) Because “[t]ort law does not impose liability on an actor for all harm factually caused by the actor’s tortious conduct,” the new Restatement chooses to use the phrase “Scope of Liability” instead. But you’re likely to see lots of lawyers and judges continuing to use the phrase “proximate cause” or “legal cause.”

The basic rule is set out in Section 29:

An actor's liability is limited to those harms that result from the risks that made the actor’s conduct tortious.

But that basic rule is complicated by at least three forms of fortuity: the unexpected victim; the unexpected harm; and intervening events. We will consider how these influence who is held liable, and for what.


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September 13, 2013

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Pam Karlan

Professor of Law

Stanford Law School

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