‘Irresistible Impulse’ and Moral Responsibility

Should the insane and the mentally ill be held morally responsible for their actions? To answer ‘No’ to this question is to classify the mentally abnormal as not fully human: and indeed legal tradition has generally oscillated between assimilating the insane to brutes and assimilating them to children below the age of discretion, neither of these two categories being accountable in law for what they do. In what respect relevant to moral responsibility were the insane held to resemble brutes and children? In the case of brutes, the answer seems to have been that the doings of the insane appeared to lack whatever it is that marks out human actions as distinctively human. What the insane did could not be thought of as issuing from deliberation, or as capable of having issued from deliberation, but seemed rather to be the result of the unbridled operation of nature — if a diseased nature. The natural comparison with insane killings seemed to be, for example, the killing of birds by cats. This distinction between animal doings and human actions does not depend on Cartesian views about the workings of animals; the operation of nature need not be thought of as mechanical. The thought is simply that where there is no room for deliberation there is no room for moral appraisal. Children, on the other hand, though capable of distinctively human action — i.e. of deliberating about what they do — were held not to be capable of the relevant kind of deliberation: for they were held ‘not to know the difference between right and wrong’.