The general principle of our law is that loss from accident must lie where it falls, and this principle is not affected by the fact that a human being is the instrument of misfortune. But relatively to a given human being anything is accident which he could not fairly have been expected to contemplate as possible, and therefore to avoid. In the language of the late Chief Justice Nelson of New York: "No case or principle can be found, or if found can be maintained, subjecting an individual to liability for [95] an act done without fault on his part.... All the cases concede that an injury arising from inevitable accident, or, which in law or reason is the same thing, from an act that ordinary human care and foresight are unable to guard against, is but the misfortune of the sufferer, and lays no foundation for legal responsibility." /1/ If this were not so, any act would be sufficient, however remote, which set in motion or opened the door for a series of physical sequences ending in damage; such as riding the horse, in the case of the runaway, or even coming to a place where one is seized with a fit and strikes the plaintiff in an unconscious spasm. Nay, why need the defendant have acted at all, and why is it not enough that his existence has been at the expense of the plaintiff? The requirement of an act is the requirement that the defendant should have made a choice. But the only possible purpose of introducing this moral element is to make the power of avoiding the evil complained of a condition of liability. There is no such power where the evil cannot be foreseen. /2/ Here we reach the argument from policy, and I shall accordingly postpone for a moment the discussion of trespasses upon land, and of conversions, and will take up the liability for cattle separately at a later stage.