§ 129 Two Classes of Wrongful Acts
Every wrong is an act which is mischievous in the eye of the law—an act to which the law attributes harmful consequences. These consequences, however, are of two kinds, being either actual or merely anticipated. In other words, an act may be mischievous in two ways—either in its actual results or in its tendencies. Hence it is, that legal wrongs are of two kinds. The first consists of those in which the act is wrongful only by reason of accomplished harm which in fact ensues from it. The second consists of those in which the act is wrongful by reason of its mischievous tendencies, as recognised by the law, irrespective of the actual issue. In the first case there is no wrong or cause of action without proof of actual damage; in the second case it is sufficient to prove the act itself, even though in the event no harm has followed it.
For example, if A. breaks his contract with B, it is not necessary for B. to prove that he was thereby disappointed in his reasonable expectations, or otherwise suffered actual loss, for the law takes notice of the fact that breach of contract is an act of mischievous tendency, and therefore treats it as wrongful irrespective of the actual issue. The loss, if any, incurred by B. is relevant to the measure of damages, but not to the existence of a cause of action. So if I walk across another man’s field, or publish a libel upon him, I am responsible for the act without any proof of actual harm resulting from it. For trespass and libel belong to the class of acts which are judged wrongful in respect of their tendencies, and not merely in respect of their results. In other cases, on the contrary, actual damage is essential to the cause of action. Slander, for example, is in general not actionable without proof of some loss sustained by the plaintiff, although libel is actionable per se. So if by negligent driving I expose others to the risk of being run over, I am not deemed guilty of any wrong until an accident actually happens. The dangerous tendency of the act is not in this case considered a sufficient ground of liability.
With respect to this distinction between wrongs which do and those which do not, require proof of actual damage, it is to be noticed that criminal wrongs commonly belong to the latter class. Criminal liability is usually sufficiently established by proof of some act which the law deems dangerous in its tendencies, even though the issue is in fact harmless. The formula of the criminal law is usually: “If you do this, you will be held liable in all events,” and not: “If you do this you will be held liable if any harm ensues.” An unsuccessful attempt is a ground of criminal liability, no less than a completed offence. This, however, is not invariably so, for criminal responsibility, like civil, sometimes depends on the accident of the event. If I am negligent in the use of firearms, and kill some one in consequence, I am criminally liable for manslaughter; but if by good luck my negligence results in no accomplished mischief, I am free from all responsibility.
As to civil liability, no corresponding general principle can be laid down. In some cases proof of actual damage is required, while in other cases there is no such necessity; and the matter pertains to the detailed exposition of the law, rather than to legal theory. It is to be noted, however, that whenever this requirement exists, it imports into the administration of civil justice an element of capriciousness from which the criminal law is commonly free. In point of criminal responsibility men are judged by their acts and by the mischievous tendencies of them, but in point of civil liability they are often judged by the actual event. If I attempt to execute a wrongful purpose, I am criminally responsible whether I succeed or not; but my civil liability will often depend upon the accident of the result. Failure in a guilty endeavour amounts to innocence. Instead of saying: “Do this, and you will be held accountable for it,” the civil law often says: “Do this if you wish, but remember that you do it at your peril, and if evil consequences chance to follow, you will be answerable for them.”