property for some temporary purpose promised to return it. Such a case

is lending; for before the days of coined money, the difference between lending a horse to go to the next town and lending ten sheep to enable the borrower to pay a composition is not perceptible. Thus another starting point of liability is recovery of a thing certain, or what was originally the same, a sum certain, promised in such wise as to endanger the general security if the promise is not carried out. In Roman law, the condiction, which is the type of actions in personam, and thus the starting point historically of rights in personam and of theories of obligation, was at first a recovery of a thing certain or a sum certain due upon a promise of this sort. In juristic terms, the central idea of the beginnings of liability is duty to make composition for or otherwise avert wrath arising from the affronted dignity of some personality desirous of vengeance, whether an injured individual, a god or a politically organized society. Greek law and Roman law give the name of "insult" to legally cognizable injury to personality. Insult to a neighbor by injury to him or to one of his household, insult to the gods by impious breach of the promise they had witnessed, insult to the people by wanton disregard of the undertaking solemnly made in their presence, threatened the peace and order of society and called for legal remedy.

Lawyers begin to generalize and to frame conscious theories in the later part of the stage of the strict law. At first these theories are analytical rather than philosophical. The attempt is to frame general formulas by which the rigid rules of the strict law may be reconciled where they overlap or conflict or may be distinguished in their application where such overlapping or conflict threatens. By this time, the crude beginnings of liability in a duty to compound for insult or affront to man or gods or people, lest they be moved to vengeance, has developed into liability to answer for injuries caused by oneself or done by those persons or those things in one's power, and liability for certain promises made in solemn form. Thus the basis of liability has become twofold. It rests on the one hand upon duty to repair injury. It rests on the other hand upon duty to carry out formal undertakings. It is enough for this stage of legal development that all cases of liability may be referred to these two types and that useful distinctions may be reached therefrom. Consideration of why one should be held to repair injury, and why he should be held to formal undertakings, belongs to a later stage.

Juristic theory, beginning in the transition from the strict law to the stage of equity or natural law, becomes a force in the latter stage. As the relations with which the law must deal become more numerous and the situations calling for legal treatment become more complicated, it is no longer possible to have a simple, definite, detailed rule for every sort of case that can come before a tribunal, nor a fixed, absolute form for every legal transaction. Hence, under the leadership of philosophical jurists, men turn to logical development of the "nature" or ideal form of situations and to ethical ideas of what "good faith" or "good conscience" demands in particular relations or transactions. The strict law, relying on rule and form, took no account of intention as such. The words took effect quite independently of the thought behind them. But as lawyers began to reflect and to teach something more than a class or professional tradition, as they began to be influenced by philosophy to give over purely mechanical methods and to measure things by reason rather than by arbitrary will, emphasis shifted from form to substance; from the letter to the spirit and intent. The statute was thought of as but the lawmaker's formulation of a principle of natural law. It was not the uerba that were efficacious, as in the strict law, which had inherited the primitive faith in the power of words and thought of the legal formula as if it were a formula of incantation possessing inherent magical force. It was the ratio iuris, which transcended words and formulas. So also the traditional rule was not a magic formula discovered by our fathers. It was a customary expression of a principle of natural law. Likewise the formal transaction was not a bit of private magic employed to conjure up legal liability. It was the clothing in legally recognized vestments of an intention to do what reason and good faith demand in a given situation. When form and intention concurred the promisor must answer for what he undertook. When the form used did not express or went beyond the intention or was the product of an apparent but not a real intention, the promisee was not to be enriched unjustly at the promisor's expense on the sole basis of the form. Moreover the duty was to be one of doing what good faith demanded, not one of doing literally and exactly what the letter of the undertaking called for. And although there was no express undertaking, there might be duties implied in the relation or situation or transaction, viewed as one of good faith, and one might be held to a standard of action because an upright and diligent man, who was his own master, would so act. Such is the mode of thinking in the classical period of the Roman law and it is closely paralleled by an independent development of juristic thought in the rise of equity and the absorption of the law merchant in our law.

It was easy to fit the two categories, delict and formal undertaking, which had come down from the strict law, into the new mode of thought. The typical delict required dolus--intentional aggression upon the personality or the substance of another. Indeed Aquilian culpa, in which the fault did not extend to intentional aggression, is a juristic equitable development. Hence when the legal was identified with the moral, and such identification is a prime characteristic of this stage, the significant thing in delict seemed to be the moral duty to repair an injury caused by wilful aggression. The legal precept was alienum non laedere. Also the duty to perform an intentional undertaking seemed to rest on the inherent moral quality of a promise that made it intrinsically binding on an upright man. The legal precept was suum cuique tribuere. Thus liability seemed to flow from intentional action--whether in the form of aggression or in the form of agreement. The "natural" sources of liability were delict and contract. Everything else was assimilated to one or the other of them. Liability without fault was quasi-delictal. Liability imposed by good faith to prevent unjust enrichment was quasi-contractual. The central idea had become one of the demands of good faith in view of intentional action.

In the nineteenth century the conception of liability as resting on intention was put in metaphysical rather than ethical form. Law was a realization of the idea of liberty, and existed to bring about the widest possible individual liberty. Liberty was the free will in action. Hence it was the business of the legal order to give the widest effect to the declared will and to impose no duties except in order to effectuate the will or to reconcile the will of one with the will of others by a universal law. What had been a positive, creative theory of developing liability on the basis of intention, became a negative, restraining, one might say pruning, theory of no liability except on the basis of intention. Liability could flow only from culpable conduct or from assumed duties. The abstract individual will was the central point in the theory of liability. If one was not actually culpable and yet established legal precepts which were not to be denied held him answerable, it was because he was "deemed" culpable, the historical legal liability being the proof of culpability. If he had not actually assumed a duty, and yet established legal precepts which were not to be denied held him to answer for it, this must be because he had assumed some relation or professed some calling in which an undertaking to that effect was "implied" or had participated in some situation in which it was "implied,"--the implication being a deduction from the liability. The bases of liability were culpable conduct and legal transaction, and these came down to an ultimate basis in will. The fundamental conception in legal liability was the conception of an act--of a manifestation of the will in the external world.

Roman law and English law begin with a set of what might be called nominate delicts or nominate torts. In Roman law there were furtum (conversion), rapina (forcible conversion) and iniuria (wilful aggression upon personality). All these involved dolus, i.e. intentional aggression. The lex Aquilia added damnum iniuria datum (wrongful injury to property). Later there were added what might be called the equitable delicts of dolus (fraud) and metus (duress). Here also there was wilful aggression, and the delict of dolus gets its name from the intentional misleading that characterizes it in Roman law as it does deceit in English law. In damnum iniuria datum, a wider conception of fault, as distinguished from intentional aggression, grew up by juristic development, and Aquilian culpa, that is, a fault causing injury to property and therefore actionable on the analogy of the lex Aquilia, furnished the model for the modern law. All these may be fitted to the will theory and modern systematic writers regularly do so. But noxal liability for injury done by a child or slave or domestic animal did not fit it, nor did the liability of a master of a ship, an innkeeper or a stable keeper to respond without regard to fault. Liability for injury done by child or slave or domestic animal was enforced in a noxal action on the analogy of the action which lay for the same injury if done by the defendant in person. Hence procedurally it seemed liability for a delict involving intentional aggression, and it was possible to say that there was fault in not restraining the agency that did the injury, although no fault had to be shown nor could absence of fault be shown as a defence. There was fault because there was liability, for all liability grew out of fault. Such treadings on the tail of its own argument are very common in legal reasoning. Likewise in the case of the absolute liability of the master of a ship, the innkeeper and the stable keeper, the institutional writers could say that they were at fault in not having proper servants, although here also fault need not be established by proof nor could want of fault be made a defence. As procedurally these liabilities arose in actions on the facts of particular cases, the jurists at first lumped them with many other forms of liability, which were not in fact dependent on intention and were enforced in actions in factum, as obligations arising from the special facts of cases (obligationes ex uariis causarum figuris). Later they were called quasi-delictual obligations and they are so designated in the fourfold classification of the Institutes. Buckland has remarked that in almost all of the liabilities included under quasi-delict in the Institutes there is liability at one's peril for the act of another, especially for one's servant, as in the noxal actions, the actio de deiectis et diffusis (for things thrown or poured from buildings upon a way) and the actio de recepto against an innkeeper. In other words, in these cases one was held without regard to fault for injuries incidental to the conduct of certain enterprises or callings and for failure to restrain potentially injurious agencies which one maintained.

Modern law has given up both the nominate delicts and quasi-delict, as things of any significance. The French civil code made the idea of Aquilian culpa into a general theory of delictal liability, saying, "Every act of man which causes damage to another obliges him through whose fault it happened to make reparation." In other words, liability is to be based on an act, and it must be a culpable act. Act, culpability, causation, damage, were the elements. This simple theory of liability for culpable causation of damage was accepted universally by civilians until late in the nineteenth century and is still orthodox. Taken up by text writers on torts in the last half of that century, it had much influence in Anglo-American law. But along with this generalization the French code preserved a liability without fault, developed out of the noxal actions, whereby parents and teachers may be held for injuries by minors under their charge, masters for injuries by their apprentices, employers for injuries by employees and those in charge of animals for injuries by such animals. Also it provided an absolute liability for injury by a res ruinosa, developed out of the Roman cautio damni infecti. In the case of parents, teachers and masters of apprentices, there is only a presumption of fault. They may escape by showing affirmatively that they were without fault and that what happened could not have been prevented by diligence on their part. In the case of employers no excuse is admitted. The liability is absolute. In the case of animals, fault of the victim, inevitable accident and vis maior may be shown affirmatively by way of defence. In the case of a res ruinosa there is no presumption of fault. But if the structure fell or did injury because of a defect of construction or want of repair, the owner is liable absolutely and may not show that he had no notice of the defect and no reason to suspect it, or that it was not in his power to prevent the structure from falling.

Thus it will be seen that French law came very near to a logically consistent scheme of liability for fault, and civil liability for fault only, throughout the whole delictal field. Employer's liability remained absolute, and liability for animals but little short of absolute. For the rest there was in certain cases an imposition of the burden of proof that there had been no fault, leaving the ultimate liability to rest upon a presumed fault, if want of fault was not established. None the less this, the most thoroughgoing attempt to make delictal liability flow exclusively from culpability--to make it a corollary of fault and of fault only--fell short of complete attainment of its aim. Recent French authors do not hesitate to say that the attempt must be given over and that a new theory of civil delictal liability must be worked out. Meanwhile the same movement away from the simple theory of delictal liability for culpable causation of damage had taken place elsewhere on the Continent. Binding had subjected the culpa-prinzip to thorough analysis, and following him it had come to be rejected generally by recent German and Swiss jurists.

In the common law, as has been said, we begin likewise with a set of nominate torts--assault, battery, imprisonment, trespass on lands, trespass on chattels, conversion, deceit, malicious prosecution, slander and libel--developed procedurally through the action of trespass and the action of trespass on the case. All of these, except trespass on lands, trespass upon possession of chattels and conversion, are cases of intentional injury. Trespass on lands, trespass on chattels and conversion involve more than the general security and must be considered in connection with ideas of property. The social interest in security of acquisitions demands that we be able to rely on others keeping off of our lands and not molesting our chattels; that they find out for themselves and at their own risk where they are or with whose chattels they are meddling. But even here there must be an act. If there is no act, there is no liability. To these nominate torts, each with its own special rules, coming down from the strict law, we added a new ground of liability, namely, negligence, going on a principle, not of duty to answer for aggression, but of duty to answer for injuries resulting from falling short of a legal standard of conduct governing affirmative courses of action. Some, indeed, sought to give us a "tort of negligence" as a nominate tort. But it was soon recognized that in negligence we have a principle of liability dependent upon a standard, not a tort to be ranged alongside of assault or imprisonment. Later, with the rise of doctrines as to injury to advantageous relations and the failure of negligence to account for all unintended harms of which the law actually was taking note, we developed an indefinite number of innominate torts. Today with the obsolescence of procedural difficulties, there is no reason why we should not generalize, as the civil law did at the beginning of the last century; and such a generalization was attempted in the last third of the nineteenth century. It became orthodox common law that liability was a corollary of fault. So far as established common-law rules imposed a liability without fault, they were said to be historical exceptions, and some of our courts, under the influence of this theory, were willing to go a long way in abrogating them. Liability, without regard to fault, for the acts of servants and employees was reconciled with this theory by the fiction of representation, exposed long ago by Mr. Justice Holmes and later by Dr. Baty. Finally it came to be thought that no liability without fault was not merely common law but was natural law and that any legislative imposition of such liability was arbitrary and unreasonable in itself and hence unconstitutional. On that theory, the New York Court of Appeals held workmen's compensation unconstitutional, and a minority of the Supreme Court of the United States recently announced the same proposition.

Because of its implications for constitutional law, in view of the increasing frequency of legislation imposing responsibility at one's peril in certain enterprises, in the case of certain dangerous agencies and in situations where it is felt that the loss should be borne by all of us rather than by the luckless individual who chances to be hurt, the basis of tort liability has become a question of moment beyond the immediate law of torts. It is a practical question of the first importance, as well as a theoretical question of interest, whether we are to generalize our whole system of tort liability by means of one principle of liability for fault and for fault only, as the French sought to do and as we later sought to do largely under their influence, or, on the other hand, are to admit another source of delictal liability alongside of fault, as the French law does in fact and is coming to do in theory, and as our law has always done in fact. For in our law as it stands one may perceive readily three types of delictual liability: (1) Liability for intentional harm, (2) liability for unintentional culpable harm, (3) liability in certain cases for unintended non-culpable harm. The first two comport with the doctrine of no liability without fault. The third cannot be fitted thereto. We must either brand cases of the third type as historical anomalies, of which we are gradually to rid ourselves, or else revise our notions of tort liability. Let us remember that the nineteenth century was well advanced before we understood the subject of negligence and that before we had convinced ourselves that no liability without fault was orthodox common law, the highest court of England had given absolute liability a new field by the decision in Rylands v. Fletcher. We are not questioning a long-established dogma in Anglo-American administration of justice, therefore, when we ask whether the orthodox theory of the last generation is adequate as an analytical statement of the law that is, or as a philosophical theory of the law that ought to be. My own belief is that it is neither.

Suppose that instead of beginning with the individual free will we begin with the wants or claims involved in civilized society--as it has been put, with the jural postulates of civilized society. One such postulate, I think we should agree, is that in civilized society men must be able to assume that others will do them no intended injury--that others will commit no intentional aggressions upon them. The savage must move stealthily, avoid the sky-line and go armed. The civilized man assumes that no one will attack him and so moves among his fellow men openly and unarmed, going about his business in a minute division of labor. Otherwise there could be no division of labor beyond the differentiation of men of fighting age, as we see it in a primitive society. This postulate is at the foundation of civilized society. Everywhere dolus is first dealt with. The system of nominate delicts or nominate torts, both in Roman law and in our law, proceeds on this postulate.

Is it not another such postulate that in civilized society men must be able to assume that their fellow men, when they act affirmatively, will do so with due care, that is with the care which the ordinary understanding and moral sense of the community exacts, with respect to consequences that may reasonably be anticipated? Such a postulate is the basis of delictal culpa, using culpa in the narrower sense, and of our doctrine of negligence. In Roman law and at one time in our law attempts were made to develop this postulate contractually. If in a transaction involving good faith--that is an informal legal transaction--one's conduct fell short of action to which the other party was justified by the understanding of upright men in expecting him to adhere, there was contractual culpa; there was a violation of a promise implied in the transaction and consequent liability. We borrowed something of this mode of thought from the Romans in our law of bailments and hence think indifferently in terms of tort or