Notwithstanding what is here said, the cases of infancy and intoxication (as we shall see hereafter) cannot be looked upon in practice as affording sufficient grounds for absolute impunity. But this exception in point of practice is no objection to the propriety of the rule in point of theory. The ground of the exception is neither more nor less than the difficulty there is of ascertaining the matter of fact: viz. whether at the requisite point of time the party was actually in the state in question; that is, whether a given case comes really under the rule. Suppose the matter of fact capable of being perfectly ascertained, without danger or mistake. the impropriety of punishment would be as indubitable in these cases as in any other (see B. L {it. iv. [Exemptions]. and tit. vii. [Extenuations].).

The reason that is commonly assigned for the establishing an exemption from punishment in favour of infants, insane persons, and persons under intoxication, is either false in fact, or confusedly expressed. The phrase is that the will of these persons concurs not with the act; that they have no vicious will; or, that they have not the free use of their will. But suppose all this to be true? What is it to the purpose? Nothing: except in as far as it implies the reason given in the text.

IPML Chapter 13 Section 3