For the satisfaction of his diverse needs and the fulfillment of his various purposes, he must associate with his fellows and seek their cooperation. Such is the testimony of history. Here and there an individual or a family has subsisted apart from the rest of the human race, but that is an exception rather than a rule. The general rule is that men live, and always have lived, in social groups.
If man is social by nature, he is selfish and quarrelsome too. This aspect of the nature of man, and the instinct of living together and cooperating with one another require adjustment of behaviour according to some accepted rules. These rules prescribe a course of conduct based upon men’s need for one another. The first and the most important rule of social conduct are: “To do unto others as you would have others do unto you.” It means, that I should provide for others the same conditions of life as I wish for myself. If I wish to grow and prosper, I owe it to others that they, too, should have the same conditions of life as I wish for myself. When I allow others what I wish for myself, I recognise my obligations to others, while establishing my claims on others. Realization of this fact is a way of regulating human conduct.
But all conduct in society must conform to certain set rules of common behaviour. The rules governing a society may be few or many. They can range from a few primitive traditions, handed down orally, from one generation to another, or to the whole complex set of constitutional and governmental regulations which we associate with the modern State. A prerequisite of such a society is that it must be properly organised. An unorganised society is more a mob than a society and the mob is subject to no restraint.
An organised society must also be territorially settled. People do not develop a community of interests unless they live a settled life occupying a definite territory distinct from other communities similarly organised. Mutual adjustment and cooperation, a life to share common weal and woe, is the sine qua non of a common life on a common land.
Then, an organised society requires the presence of some individuals to enforce rules of universal application for uniform behaviour and ensure their observance. In the absence of such an agency, there is neither cohesion nor unity of purposes for which men had organised themselves and settled down territorially. The society, thus organised, is called the State, rules which determine social conduct are the laws of the State and the individuals who enforce the laws and see that they are equally observed by all constitute its government.
The subject that deals with man in relation to the State and its government is called Political Science. Political Science may be defined, in its simplest form, as the study of man in the process of governing himself.