The question of punishment is one which has always interested and usually puzzled moralists, and which forms a crucial example for the testing of moral theories. A utilitarian theory, whether of the hedonistic or of the ‘ ideal ’ kind, if it justifies punishment at all, is bound to justify it solely on the ground of the effects it produces. The suffering of pain by the person who is punished is thought to be in itself a bad thing, and the bringing of this bad thing into the world is held to need justification, and to receive it only from the fact that the effects are likely to be so much better than those that would follow from his non-punishment as to outweigh the evil of the pain.