The essence of human intelligence is the ability to adapt and survive. Rosamund Stock sees that markets render us collectively stupid and argues that only pluralist, participative decision-making processes can enable us to survive and prosper as a society.
Democracy is both a way of making collective decisions and a form of participation in society.
The way we participate affects the decisions we make and our role in the decision process affects our membership of society. If a society can draw upon the expertise and knowledge of all its citizens, then it is more likely to be able to make adaptive decisions in a changing environment. If the decision making process involves the citizens of a society then they will see themselves as part of that society and take on a responsibility for their actions within it. The first is important because participation in decisions means that people feel they own them, and thus will take some responsibility for their implementation. Having a voice in decision processes is one of the biggest factors in their appearing fair.