386 HARVARD LAW REVIEW. The general idea of Responsibility seems to involve in Anglo- American law three main notions : — 1. Causation. We find, first, a fundamental notion that the de- fendant must have caused the harm in question. This is to-day almost axiomatic ; although in primitive and mediaeval times many kinds of connection, short of causation, sufficed to fix liability. The superstitious attitude of the period made accursed the man and the thing by whom the offence came, whether in strictness it was or was not caused thereby.^ The accepted ethical axiom of to-day, causation, rarely gives rise to legal difficulty in its applica- tion, except in one or two cases commonly treated under the law of Damages, e. g. whether a particular disease was caused by a carrier's negligence or by a surgeon's bungling, whether a loss of business profits was caused by alleged unlawful conduct or by ex- ternal events, etc. A special problem is presented where several wrong-doers have co-operated and the apportionment of Responsi- bility to the real source is necessary; as where dogs of several persons combine in worrying sheep. Usually the knot is cut in Alexandrine fashion ; as where the liquor-damage statutes provide that, during the period of disability of a father by intoxication to support his famih', any liquor-seller furnishing liquor during that time shall be liable ; or where the common-law principle makes any one of joint tort-feasors liable for the whole damage. 2. Activity, Next we find a cardinal principle (not without ex- ceptions) requiring that the person to be made responsible must be fixed with an initiating act or activity, an exercise of volition, remote or near, without which he cannot be brought to bar. This is the broader phase of the well-known principle that an action of tort does not lie for a mere nonfeasance. All the harm in the world may come to X, but Y cannot be made responsible unless we can fix upon him some active interposition.^ Thus, one who, 1 See the article in 7 Harv. Law Rev. 315 ff. 2 It is a common error to suppose that " negligence," as the source of culpability, involves often or usually a mere omission, a not-doing as distinguished from positive doing in a careless way. But all negligence, in Torts, is founded ultimately on a do- ing an action. If the source is in appearance an omission, as where an engineer fails to ring the bell or to keep a lookout, it is reducible to a mismanagement, an improper doing. Speaking accurately, the term " negligence " expresses merely the relation between this original act and the harmful consequence, i. e. the probability of the harm; and therefore the culpability consists in putting one's hand to the deed (thus always an Action) in the face of this probability of harm. Mr. Justice Holmes has pointed this out long ago (Common Law, pp. 152, 161) : " In all these cases it will be found that there has been a voluntary act on the part of the person to be charged. ... It is
