How is a social decision made out of individual members' decisions? This is one of the primary questions in the social sciences. Logic and Social Choice provides an answer to the topic by the application of mathematical logic. Yasusuke Murakami formulates social decision-making in logical terms, and shows that an analysis of social decision is equivalent to a logical calculus in many-valued logic. The logical conditions are then derived for various types of societies, especially for democracy. This foundation enables the author to discuss such topics as the relation between direct...