This chapter focuses on the notation and definitions required to represent the theoretical primitives of formal theory – alternatives, outcomes, and preferences. Although this focus may make reading difficult for those who are encountering these ideas for the first time, this material must be mastered if formal political theory is to be understood in more than a superficial way.

We begin with two assumptions: methodological individualism and purposeful action. Methodological individualism holds that we can understand social processes and outcomes in terms of people's preferences and choices. This assumption may seem strange to the student of politics, who is concerned primarily with collectivities such as interest groups, political parties, or legislatures, and for whom the most useful explanatory concepts assume a group consciousness. Such concepts, though, are generally little more than journalistic conveniences that afford us the luxury of not having to delve into the complexities of organizations and institutions. But interest groups cannot lobby: Only their members can opportune legislators. Similarly, a legislature cannot “hold” a norm: Only its members can share a consensus about acceptable standards of action and penalties for violations of those standards.

Obviously, it is convenient to speak of “society preferring clean air,” “firms maximizing profits,” or “the Office of Management and Budget setting national economic policy.” Furthermore, no one should dispute that social interaction conditions people's preferences and choices. The assumption of methodological individualism is but a reminder that only people choose, prefer, share goals, learn, and so on, and that all explanations and descriptions of group action, if they are theoretically sound, ultimately must be understandable in terms of individual choice.