[MUSIC] Mr. Kendal's victory before Chief Judge Shaw happened more than 150 years ago. But it tells us something about American tort law that remains true today. Brown vs Kendall pronounced that America's tort system is and should be a generally fault based system. If a man or woman is to be found liable for an accident in a typical case, it must be shown that they were at fault. He or she is at fault only if they acted intentionally. We now say, "knowingly" or "purposefully.". Or if they acted negligently. A negligent person is one who acts without the ordinary care or prudence suitable for the circumstances. We say they also act as a reasonable person of ordinary prudence. A reasonable person of ordinary prudence. Judge Shaw, and influential state judges after him, rejected the strict liability interpretations of the common law. A New York court bluntly rejected English strict liability rules as unsuitable for a new world, nation building nation. In the case of Losee vs Buchanan, a boiler exploded in a paper mill, damaging adjacent property. The owner of the property went to court to recover based on a strict liability theory. But the New York court, like the Massachusetts court, decided that plaintiffs need to establish fault. The injured plaintiff had to prove by a preponderance of the evidence that the owner of the boiler either intended the harm, which he clearly did not, or had been negligent, which was possible. It was not enough that his boiler exploded, the question for the judge and jury is whether the boiler exploded as a result of the negligence of it`s owner or his employees. Thanks to courts in Massachusetts and in New York, liability for accidental injury is generally based on a proof of negligence. American scholars debate whether the rules of negligence are more efficient or fair than rules of strict liability. Some legal historians claim the Rule of Fault was embraced by the 19th Century judges, because it was implicitly or explicitly thought to be helpful to the cause of American Capitalism. The spirit of entrepreneurship and innovation can fly freer if one doesn't have to worry about being strictly liable for inevitable, but unwanted accidents. It has been suggested that the American rule of Law, our social contract promises us security and freedom. Tort Liability, based on the fault principle, arguably enhances our freedom, while respecting our need for security. How so? Well, negligence liability disincentivizes carelessness and unreasonable risk taking. Free enterprise, an opportunity in theory open to all, exploits dangers with supposed benefits for all. Trains are dangerous but beneficial to the public. And so are factories, tall buildings, bridges, chemicals, boilers, and dams. The price of utter safety would be a lack of progress and productivity. Now, is this truth, ideology. I'm not asking you to accept these political economic assumptions. I merely report them as perspectives voice in our courts that may help to explain a central feature of American tort law. American tort law generally requires that those who bring a civil lawsuit prove that the person who injured them was at a fault. This is a distinctive though debated feature of our law. Sometimes referred to as the fault system. In the case of fighting dogs, Brown vs Kendal one man injured another accidentally. Under American tort law if this accident was a result of negligence, there would be liability. However, if the accident was not due to negligence, there would not be a liability. But what, exactly, is negligence? The contemporary definition of negligence builds on the 19th century concept articulated by Judge Shaw. In contemporary tort law, negligence is defined as a breach of duty of care owed to others, which causes injury to a third person or a person's property. The duty owed in most cases, the law says, is the duty of the reasonable person of ordinary prudence under the circumstances. So American courts and legal experts suggest that the reasonable person thinks about cost and benefits. If a small inexpensive expenditure of care can avert a more expensive and probable injury, that care should be undertaken. Arguably, beating dogs with a long stick when one knows another man is standing close by, but out of sight is negligent. To make swinging a stick more careful, perhaps one should shout a warning. Watch out, stand back. The cost of that burden of care is far less than the cost of forseeable injury to the man standing behind. [MUSIC]