I came upon this quote when I was working on my previous post about choosing in groups. It comes from Buchanan and Tullock’s 1959 work, The Calculus of Consent: Logical Foundations in Constitutional Democracy.
Any theory of collective choice must attempt to explain or to describe the means through which conflicting interests are reconciled. In a genuine sense, economic theory is also a theory of collective choice, and, as such, provides us with an explanation of how separate individual interests are reconciled through the mechanism of trade or exchange. Indeed, when individual interests are assumed to be identical, the main body of economic theory vanishes. If all men were equal in interest and in endowment, natural or artificial, there would be no organized economic activity to explain. Each man would be a Crusoe. Economic theory thus explains why men co-operate through trade: They do so because they are different.
Everyone has different interests and an idea of how to best accomplish a tasks. A healthy organization/society/state has to learn how to reconcile those interests.