PENOLOGY, penal science, that part or division of crimin ology which concerns itself with the philosophy and practice of society in its efforts to repress criminal activities. As the term signifies (Lat. poena, pain, suffering), penology has stood in the past and, for the most part, still stands for the policy of inflicting punishment on the offender as a consequence of his wrong-doing, hut it may reasonably be extended to cover other policies, not punitive in character, such as probation, medical treatment and education, aimed at the cure or rehabilitation of the offender; and this is, in fact, the accepted present sense of the term.
The principal aims of penal science are : to 'bring to light the ethical bases of punishment, along with the motives and purposes of society in inflicting it ; to make a comparative study of penal laws and procedures throughout human history and particularly at the present time; and, finally, to evaluate the social consequences of the policies in force at a given time. Thus conceived, penology represents a grouping of studies, some of which, dealing with the aims and the moral or social justifications of punishment, date from a remote past, while others, having to do with the wider social implications of the system, have scarcely yet made a begin ning. As a modern and, therefore, a critical science, penology may properly be regarded as a serious effort to effect a revaluation of the concepts, theories and assumptions regarding punishment for crime which have for 2,000 years found expression in legal and philosophical literature, as well as in the penal law.
The exploration of the animating forces of the system of pun ishment carries the penologist far back into human nature as well as into human history. Back of any scheme of punishment is a policy and that policy is, in its turn, the fruit of a living sentiment or the result of a struggle between competing sentiments. The policy that has most persistently dominated and which is still a powerful if not controlling factor in penal legislation and practice is that of retribution, offspring of the sentiment of vengeance.
Whether the offence to be compensated for is confined to an individual victim or is conceived of as an injury to the social group to which he belongs, the immediate reaction is resentment and this can be appeased only by expiation or retribution. This, with primitive literalness, gave to early society at a comparatively ad vanced stage the rule: life for life, eye for eye, tooth for tooth, limb for limb. It still survives in the death penalty for murder and in the drastic penalties imposed for rape and other crimes which are peculiarly offensive to the moral sentiments or to the sense of security of the community. Nearly everywhere, in the more recent stages of social development, this motive has been supplemented, but never wholly supplanted, by an unquestioning faith in the deterrent effect on potential offenders of exemplary, i.e., drastic, punishments inflicted on actual offenders, which, in practice if not in theory, comes to much the same thing.
This policy of retribution is justified and sustained by an ethical philosophy which regards punishment as an integral and inviolable element in wrong-doing, as a moral necessity, "the other half of crime." This doctrine has been consistently maintained by the intuitive or idealistic philosophers from Plato to Thomas Aquinas and from Kant to T. H. Green and his disciples. The deterrent effect of punishment has also been claimed by adherents of this school but its widespread adoption as a policy has probably been due more to the influence of the utilitarian philosophy of Bentham, Paley, John Stuart Mill and Herbert Spencer, which makes the welfare of society, "the greatest good of the greatest number," the aim of all moral activity. It is this utilitarian philosophy which is now in the ascendant in penal legislation and which governs the view of most modern penologists.