Plato was the initiator, in the philosophical literature, of the idea that punishment should look to the future, not to the past. It must be beneficial and serve some useful purpose. Beneficial to whom? The first part of Plato’s answer is striking: ‘to the offender’. Punishment should be directed at reforming offenders rather than simply penalizing them because they had offended. This idea was accepted by a succession of (non-abolitionist) thinkers. It is still with us today. Plato was presumably unaware that he was opening a loophole that could be exploited by later reformers who sought a reduction, and then finally abolition, of the death penalty: an offender sentenced to a programme of rehabilitation was not a prime candidate for execution. However, a further possible answer to Plato’s question might be: ‘(beneficial) not for the criminal but for society as a whole’. Plato also held that punishment might serve as a deterrent, and this opened the door to harsh treatment, including death, of some offenders, namely, those who were judged ‘incurable’. One might kill a murderer, or a disparager of the gods, to deter others.