Politics is a collective activity, involving people who accept a common membership or at least acknowledge a shared fate. Thus, Robinson Crusoe could not practice politics. Politics presumes an initial diversity of views, if not about goals, then at least about means. Were we all to agree all the time, politics would be redundant. Politics involves reconciling such differences through discussion and persuasion. Communication is, therefore, central to politics. Political decisions become authoritative policy for a group, binding members to decisions that are implemented by force, if necessary. Politics scarcely exists if decisions are reached solely by violence, but force, or its threat, underpins the process of reaching a collective decision. The necessity of politics arises from the collective character of human life. We live in a group that must reach collective decisions: about sharing resources, about relating to other groups and about planning for the future. A family discussion where to take its vacation, a country deciding whether to go to war, the world seeking to limit the damage caused by pollution. All are examples of groups seeking to reach decisions which affect all their members. As social creatures, politics it part of our fate. We have no choice but to practice it.