Public opinion is a term describing an ill-defined, mercurial and changeable group of individual judgments. Public opinion is the aggregate result of individual opinions--now uniform, now conflicting--of the men and women who make up society or any group of society. In order to understand public opinion, one must go back to the individual who makes up the group. The mental equipment of the average individual consists of a mass of judgments on most of the subjects which touch his daily physical or mental life. These judgments are the tools of his daily being and yet they are his judgments, not on a basis of research and logical deduction, but for the most part dogmatic expressions accepted on the authority of his parents, his teachers, his church, and of his social, his economic and other leaders. The public relations counsel must understand the social implications of an individual’s thoughts and actions. Is it, for example, purely an accident that a man belongs to one church rather than another or to any church at all? Is it an accident that makes Boston women prefer brown eggs and New York women white eggs? What are the factors that work in favor of conversion of a man from one political party to another or from one type of food to another? Why do certain communities resist the prohibition law--why do others abide by it? Why is it difficult to start a new party movement--or to fight cancer? Why is it difficult to fight for sex education? Why does the free trader denounce protectionism, and vice versa? If we had to form our own judgments on every matter, we should all have to find out many things for ourselves which we now take for granted. We should not cook our food or live in houses--in fact, we should revert to primitive living. The public relations counsel must deal with the fact that persons who have little knowledge of a subject almost invariably form definite and positive judgments upon that subject. “If we examine the mental furniture of the average man,” says William Trotter, the author of a comprehensive study of the social psychology of the individual,[4] “we shall find it made up of a vast number of judgments of a very precise kind upon subjects of very great variety, complexity, and difficulty. He will have fairly settled views upon the origin and nature of the universe, and upon what he will probably call its meaning; he will have conclusions as to what is to happen to him at death and after, as to what is and what should be the basis of conduct. He will know how the country should be governed, and why it is going to the dogs, why this piece of legislation is good and that bad. He will have strong views upon military and naval strategy, the principles of taxation, the use of alcohol and vaccination, the treatment of influenza, the prevention of hydrophobia, upon municipal trading, the teaching of Greek, upon what is permissible in art, satisfactory in literature, and hopeful in science.