The meaning of justice constitutes the subject matter of this book. It is one of the most important topics discussed in the Nicomachean Ethics for justice was often used by the Greeks in a manner that was practically synonymous with goodness. It will be recalled that in Plato's Republic the theme of the entire book was an attempt to find a satisfactory answer to the question "What is justice?". As the discussion developed it became clear that the subject was a very complicated one. It involved consideration of all that constitutes the good life both for the individual and for the state as a whole. In general it may be said that Aristotle's conception of justice was essentially in harmony with what Plato had taught although his manner of presenting it was more systematic in form and quite devoid of the charm and literary style which Plato had used. There is a further difference, too, in the fact that while Plato was concerned primarily with the meaning of justice in general, Aristotle gives far more attention to its meaning in relation to particular instances.
Using the concepts employed in the field of mathematics Aristotle describes justice in terms of proportion and equality. It is treating individuals with fairness to all and it is a matter of distributing goods in their right proportion. The latter is reminiscent of the doctrine of the golden mean insofar as it means that persons should not be awarded too much or too little. But in another sense justice is unlike the golden mean. It is something for which everyone should strive and no one can ever have too much of it. Justice is both an individual virtue and a social one. It refers to the actions of individuals in their relations with one another and it has to do with forms of government, the making of laws, and the system of rewards and punishment. The discussion of justice especially in relation to matters of state is developed more fully in the Politics and for this reason the major emphasis in the Ethics is given to other aspects of the subject.
The full meaning of justice is something more than can be expressed in any one of the definitions that are given. According to one of these justice may be said to consist in conformity to the laws of the land. The idea of equality is implied in this statement for it means that individuals may be treated fairly only in a society which is organized and where government operates according to laws which have been established for the good of all the people. Furthermore, these laws must be applied to all citizens without showing any favoritism to any individuals or groups of people representing special interests. It is true that the laws which have been enacted in any given society will never be more than approximations to justice in its ideal form. Nevertheless, these laws should be respected and obeyed so long as they are the recognized laws of the land for in spite of their imperfections they give to all the citizens more freedom and protection than they would have in a state of anarchy. Society should, however, always strive to make improvements in their system of laws. This becomes necessary whenever the administration of existing laws is obviously in violation of the spirit of justice in its ideal or universal form. This is implied in Aristotle's distinction between conventional justice and natural justice. In an ideal society or one in which each person voluntarily respects the rights of every other person there is no need for laws. But societies of this kind do not actually exist. The tendency to promote one's own interests even though it is at the expense of others is so strong in human nature that there is need for something to counteract it. Besides, there are always those who do act in a manner that is contrary to the public interests and society needs to be protected insofar as this is possible. For these reasons laws are necessary and penalties are imposed on those who violate them. In a well ordered society an attempt will be made to have only those laws which are fair and just to all of the citizens and the same will be true with reference to the penalties which are imposed. This is an ideal which can only be approximated in any given society because of the differences between individuals and the respective conditions under which they live. Nevertheless, it is important for the state to come as close to the ideal as they can under the existing circumstances.
Justice in regard to punishments may be conceived in two different ways. One of these is known as retributive justice and the other one as remedial or corrective justice. Retributive justice is based on the idea of equality and means that when one person has injured another he shall make restitution in an amount which is equal to the injury he has inflicted. There are some instances in which the amount can be calculated with a fair degree of accuracy. This is especially true in those cases where a money value can be placed on the injury. This cannot always be done. It then becomes necessary to find some other means in which one may make atonement for his misdeeds. In all of these instances care must be exercised to make sure that the penalty is neither too light nor too severe. Remedial justice aims not at exacting a penalty which shall be equal to the crime but rather at restoring the criminal to the point where he is able to resume a normal and law abiding place in society. This type of justice should always take precedence over the retributive form whenever the circumstances are such that reformation seems at all likely.
Another important aspect of justice has to do with the proper distribution of wealth. In Aristotle's conception of the good life material goods are regarded as only means for the achievement of spiritual values. The accumulation of money is not an end in itself. Nevertheless, it is an important means and one without which the achievement of many of life's values would be impossible. Hence, the just state will aim at distributing the wealth in a manner that will be most conducive to the realization of the good life for all of the people. This cannot be done by giving an equal amount to everyone nor by distributing the goods of society so as to meet the basic needs of all the people. In this respect Aristotle would be critical of any so-called welfare state which divides the wealth on the basis of needs alone. The trouble with this system is that it neglects the respective merits of individuals. It treats the industrious ones and the lazy one alike. This is a violation of the spirit of justice. People are unequal both in their abilities and in the efforts which they put forth to use the abilities they do have. Because of this fact any just distribution of wealth will be based on merit as well as need. To treat unequals as though they were equal is indeed one of the most flagrant forms of inequality.