Section I. INTRODUCTORY

In this chapter will be considered, the chief instances in which criminal guilt is lessened or entirely excluded owing to special circumstances or to something peculiar to the person who has brought about the actus of a crime. As previously mentioned rules of law are in the first instance stated for what we have termed the legally normal individual. We have now to consider the situation in criminal law of persons who are not, in this sense, normal. It will also be convenient to consider some sets of circumstances in which even the normal person's liability is modified, although upon examination it will be found that these modifications are really no more than applications of the general principles of responsibility which have already been discussed, and logically should have been dealt with in the last chapter. To have done so, however, would have overloaded the exposition of the main features of this branch of the law and would have tended to distract the student's attention from them. They can be grouped under the headings of Mistake, Intoxication and Compulsion.

Section 2. Mistake

MISTAKE AS A DEFENCE AT COMMON LAW

It is plain that if mistake is to be held to excuse a harmful deed the law is allowing an examination into a subjective mental element, namely the operation of the accused person's mind. This examination will only be made at the instance of the accused on whom will rest the burden of producing evidence that he was mistaken and that his conduct in the matter was due to his mistake. In this way the accused raises the defence either that he had no metis rea or, where the facts so warrant, that he should be treated as though his harmful deed had not been an actus reus. This in effect means, in simple language, that the man can claim that his present trial shall proceed on the fiction that the facts were as he had mistakenly believed them to be, and not as they really were. But if this defence is to be successful, the law requires that the following conditions shall be fulfilled.