If, therefore, there is any common ground for all liability in tort, we shall best find it by eliminating the event as it actually turns out, and by considering only the principles on which the peril of his conduct is thrown upon the actor.  We are to ask what are the elements, on the defendant’s side, which must all be present before liability is possible, and the presence of which will commonly make him liable if damage follows.

The law of torts abounds in moral phraseology.  It has much to say of wrongs, of malice, fraud, intent, and negligence.  Hence it may naturally be supposed that the risk of a man’s conduct is thrown upon him as the result of some moral short-coming.  But while this notion has been [80] entertained, the extreme opposite will be found to have been a far more popular opinion;—­I mean the notion that a man is answerable for all the consequences of his acts, or, in other words, that he acts at his peril always, and wholly irrespective of the state of his consciousness upon the matter.

To test the former opinion it would be natural to take up successively the several words, such as negligence and intent, which in the language of morals designate various well-understood states of mind, and to show their significance in the law.  To test the latter, it would perhaps be more convenient to consider it under the head of the several forms of action.  So many of our authorities are decisions under one or another of these forms, that it will not be safe to neglect them, at least in the first instance; and a compromise between the two modes of approaching the subject may be reached by beginning with the action of trespass and the notion of negligence together, leaving wrongs which are defined as intentional for the next Lecture.

Trespass lies for unintentional, as well as for intended wrongs.  Any wrongful and direct application of force is redressed by that action.  It therefore affords a fair field for a discussion of the general principles of liability for unintentional wrongs at common law.  For it can hardly be supposed that a man’s responsibility for the consequences of his acts varies as the remedy happens to fall on one side or the other of the penumbra which separates trespass from the action on the case.  And the greater part of the law of torts will be found under one or the other of those two heads.

It might be hastily assumed that the action on the case [81] is founded on the defendant’s negligence.  But if that be so, the same doctrine must prevail in trespass.  It might be assumed that trespass is founded on the defendant’s having caused damage by his act, without regard to negligence.  But if that be true, the law must apply the same criterion to other wrongs differing from trespass only in some technical point; as, for instance, that the property damaged was in the defendant’s possession.  Neither of the above assumptions, however, can be hastily permitted.  It might very well be argued