Of all the social virtues, justice is the one that has been most widely acclaimed. Whether the basis for this virtue is to be found in the order of nature or consists only in the formulations which have been developed in human minds is a question concerning which there has been considerable disagreement. Hume begins the discussion by calling attention to the fact that justice has always been regarded as something that is useful to human society. Whether this usefulness is the sole factor that is responsible for the origin of justice is a matter that needs to be examined. It is likewise a matter of dispute whether usefulness constitutes the sole foundation for the merit which has been accorded to it. As an empiricist, Hume believes that any satisfactory answer to these questions must be obtained from an examination of the conditions and circumstances that have preceded any formulation of the principles of justice or have caused them to be altered in any way.
The evidence which he presents seems to indicate quite clearly that usefulness to human society is the sole factor that is responsible for the origin of justice and for the high esteem with which it is universally held. He points out, for example, that in an imaginary society in which all the needs of people are supplied by a bountiful and beneficent nature, there would be no justice since the need for it would not arise. In a society of this kind, there would be no property rights, and any regulations concerning the holding or use of material goods would be superfluous.
Something like this type of situation prevails at the present time with reference to the free uses of air and water. The same thing is true in a primitive society where there is more than enough land to meet the needs of the entire population. Within certain limitations, this is also true of the water in the oceans of the world. The use of this water for transportation and other purposes is free to all so long as there is no interference with a similar usage on the part of other people.
Thus we see that justice comes into existence when the goods that are necessary for human welfare are not available in sufficient abundance so that everyone can have all that he wants. When this condition obtains, it becomes necessary to establish some principles for the proper distribution of the goods at hand. Private property then becomes an essential condition for the promotion of human welfare, and with the establishment of a system of rights and responsibilities, the principles of justice may be said to fulfill one of the major needs of human society.
The dependence of these principles of justice upon their usefulness in meeting the needs of society rather than some characteristic of nature apart from human needs can be seen from the fact that their strict enforcement is suspended whenever there are more important needs which cannot be satisfied by obedience to them. For example, in the event of a flood or a famine, people do not hesitate to appropriate whatever goods are available and necessary in order to prevent starvation or to supply whatever it takes in order to preserve human life. This is done in spite of the fact that under normal circumstances actions of this kind would be regarded as a clear violation of the principles of justice. What is known as property rights are likewise set aside in the event of a shipwreck or any other disaster in which human life is endangered.
Self-preservation always takes precedence over the principles of justice. The latter are regarded as binding only when they are able to serve as means toward the satisfaction of those ends which are considered to be of the greatest importance.
This point is illustrated again in the attitude taken by society toward the punishment of criminals. The appropriate action in regard to those who have violated the laws of the land is to deprive them of their property, their liberty, and in extreme cases even of life itself. To do these things to law-abiding citizens would indeed be contrary to the principles of justice, but in the case of criminals these principles are suspended because it is a necessary means for the protection of society. International warfare provides another instance in which the principles of justice are suspended in the interests of achieving victory over the enemy. Nations that are at war with one another have no scruples about deceiving their enemies or destroying their property and taking possession of their land.
In other words, the principles of justice are disregarded when they are not useful to the interests of those who are involved in the conflict. In all of these instances, it is evident that the rules of equity and justice owe their origin and their existence to the utility which results from their use. This is true no matter what the original state of human nature may have been. Whether the first state of humanity was the type represented by the golden age of ancient legends or that of a "war of all against all" as set forth in the writings of Thomas Hobbes, the origin and status of the principles of justice is essentially the same.