The problem with opinions is that, once having arrived at them, we then think we know all there is to know about a situation, and that no further thought is required. We are all guilty of this, on the left as well as on the right.

People in the Public Relations Industry refer to themselves as “opinion makers”. They work through people they call opinion leaders. Opinion leaders are people who are able to influence other people in their thinking. In other words, their job is to implant opinions into other people’s heads.

The pioneer of the modern Public Relations Industry, Edward Bernays, said: "If we understand the mechanisms and motives of the group mind, it is now possible to control and regiment the masses according to our will without their knowing it... In almost every act of our daily lives, whether in the sphere of politics or business, in our social conduct or our ethical thinking, we are dominated by the relatively small number of persons ... who understand the mental processes and social patterns of the masses. It is they who pull the wires which control the public mind."

In fact even the term “Public Relations” is a public relations exercise. What Bernays meant was propaganda, but he recognised that that word had negative connotations, so invented the term “public relations” to cover it.

An early success for Bernays’ newly conceived industry was a campaign to persuade women to smoke. This was in the early 1920s. There was already a great social movement towards women’s emancipation, but Bernays managed to link this to the idea of women smoking. Smoking in public was interpreted as an act of personal and political emancipation.

You can see from this example that the industry is both opportunistic and clever. The movement toward women’s emancipation already existed. Bernays’ great achievement was to link this to a specific product. It was to take a thought that already existed and to turn it to particular ends. So cigarettes became a symbol of individual emancipation. Women adopted the symbol en masse without realising that they were being manipulated.

There’s an irony here. The more general an idea becomes, the more people will adopt it for themselves. The mass media’s great success is that it makes an appeal to the individual. People use certain products in order to display their individuality. You hear people talking about their movies, their music, their food, their lifestyle, as if these things really belonged to them. Adverts for hair gel, for example, emphasise individuality. Individuality is contrasted with regimentation, while the product is used by millions of people. Millions of people all wearing the same hair gel, all doing so in order to be unique.

Likewise people have their opinions. They wear their opinions like hair gel. It’s a statement of individuality. I’m this kind of person, I’m that kind of person. We divide ourselves into tribes using our opinions. Once we discover what a person’s opinions are then we think we can assess them. We can dismiss them or embrace them on the basis of their opinions. We don’t have to listen to them any more. We know what their opinions are. We check their opinions against our own in order to judge them. Whole swathes of the human race are categorised in this way. We are like football supporters at a football match, wearing our opinions like scarves around our necks to show which side we are on.