This book features mathematical and formal philosophers' efforts to understand philosophical questions using mathematical techniques. It offers a collection of works from leading researchers in the area, who discuss some of the most fascinating ways formal methods are now being applied. It covers topics such as: the uses of probable and statistical reasoning, rational choice theory, reasoning in the environmental sciences, reasoning about laws and changes of rules, and reasoning about collective decision procedures as well as about action. Utilizing mathematical techniques has been very fruitful in the traditional domains of formal philosophy - logic, philosophy of mathematics and metaphysics - while formal philosophy is simultaneously branching out into other areas in philosophy and the social sciences. These areas particularly include ethics, political science, and the methodology of the natural and social sciences. Reasoning about legal rules, collective decision-making procedures, and rational choices are of interest to all those engaged in legal theory, political science and economics. Statistical reasoning is also of interest to political scientists and economists.

The square of opposition is a simple geometrical figure expressing some fundamental ideas about cognition. It is based on Aristotle's philosophy and has been fascinating people for two thousand years. The three notions of opposition presented in the square can be applied to analyze and understand such diverse subjects as reasoning about mathematical objects, perceptions of reality, speech acts, moral reasoning and reasoning about possibility. This book presents recent research papers dealing with the history and philosophy of the square, new diagrammatic and mathematical developments arising from it, and its applications to the fields of linguistics, psychology and argumentation. It also includes a DVD composed of events from the first world congress on the square of opposition held in June 2007 in Montreux, featuring some of the speeches and presentations of the participants, like the professors Pascal Engel, Laurence Horn, Terence Parsons, Jan Wolenski. Further, the DVD contains extracts of a square jazz show which was composed and presented for this occasion and extracts of the movie "The Square of Salome". The movie, which was produced for this event, is a remake of the famous biblical story using the square to display the relations between the main characters.