Source: https://h2o.law.harvard.edu/playlists/88
Timestamp: 2019-04-26 14:42:00+00:00

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Cause in fact is a prerequisite for torts liability. It must be more likely than not that but for a liable person's action/omission, the harm would not have occurred. If we cannot prove this “more likely than not” standard, then in most cases the harm is too uncertain for a court to shift liability from where it fell.
However, this standard begins to run into problems in two situations. First, when the standard falls short, yet our intuition and morality tell us that something is clearly wrong. And second, when too much evil occurs and we're unable to sort out which wrong act was the cause in fact.
This playlist attempts to lay out a basic doctrine of cause in fact, without yet worrying about problems of foreseeability. It first looks at Perkins v. Texas and New Orleans Ry. Co., a basic case with clear negligence and obvious harm, but where causation problems prevents recovery.
General Electric Co. v. Joiner and Anderson v. Minneapolis, St. P. & S. St. M. R.R. Co. present situations where there are multiple different causes. In the first, the district court found as a matter of law that expert testimony was not reliable enough to make one specific cause more likely than not. In the other, the court sent it to the jury with very detailed (perhaps incomprehensible?) instructions about how different causes could combine together.
In Litzman v. Humboldt County and Skipworth v. Lead Industries Association, we look at causation when there are multiple defendants and it is not possible to identify which one of them was responsible for the harm, yet harm clearly happened due to the negligence of at least one defendant. Litzman explains the generally accepted theory of alternative liability in which two defendants who both acted negligently but could not both have caused the same harm can each be held liable for 100% of the harm, then left to each other to sort the proper share of responsibility. Skipworth explains the much more controversial theory of market-share liability, which nearly does away with causation entirely in situations where many companies all negligently placed something harmful into the stream of commerce.
1 Show/Hide More Perkins v. Texas and New Orleans Ry. Co.
This case provides a basic introduction to the concept of cause in fact. Harm definitely happened, and it definitely came because a speeding train collided with a car. But, would the accident have happened even if the train did not speed? Did the speeding even make a difference?
This case presents an example of a situation where there are too many causes in fact. Here, it’s difficult to actually tell what was more likely than not to have caused the plaintiff’s cancer because there were chemicals, smoking, and conflicting scientific evidence that make it unclear what might have caused the lung cancer. This case is also an example of a court making a legal holding that a particular substance did not cause a certain harm, preventing the issue from ever reaching a jury.
3 Show/Hide More "Two Fires" Anderson v. Minneapolis, St. P. & S. St. M. R.R. Co.
This case deals with cause in fact liability when it’s clear from the evidence that the defendant railroad did start a fire. The issue is whether it was the railroad’s fire that caused the property damage, whether it was some other fire all by itself, or whether the two fires mixed together and caused the damage.
Explosion could not have been the fault of both people, but since we can’t prove which one actually was at fault, we’ll hold them joint and severally liable and let them sort it out later, since the defendants are in the best position to know and provide evidence of who was actually at fault.

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