Kangilem and Foukou were representatives of a great era of modern thought, on which we still depend today, despite trends and fleeting enthusiasms. I hope I have contributed, even a little, to maintaining an interest in these two projects that intersect and for which I am convinced that they remain necessary for both the theoretical understanding of our present and its practical transformation, at a time when, more than ever, we need strong concepts to orient ourselves in the world and in thought.

(from the author's preface to the Greek edition)

What are rules? Why does social life confront rules? Where do they draw their power from? From life, explains Kangilem. From something, according to Foukou, that could be called history. How do life and history effectively combine their actions? This is the question to which Kangilem and Foukou, two of the greatest thinkers of the 20th century who were engaged in a continuous dialogue, never ceased to return.

Five texts by Pierre Massere explore how the theme of rules evolved in Kangilem and Foukou. Three additional texts, added to the Greek edition, investigate the broader philosophical and scientific implications of the projects of Kangilem and Foukou.