Preface by Jean Gayon

The contents and structure of this work require some explanation. The original French title, La connaissance de la vie aujourd'hui, is intended to echo that of a collection of texts published by Georges Canguilhem in 1952, La connaissance de la vie1 (Knowledge of Life, 2008 [1965]). This modest book, which I consider to be the pinnacle of Canguilhem's work, has been present at the back of my mind throughout my career, forming a silent but omnipresent framework for my whole way of thinking. My aim has been, more or less consciously, to imitate it. As with any imitation, my work deviates in certain respects from the paradigm in terms of topics, intellectual approach, and normative framework, but the method used is essentially the same, based on the conviction that temporal and intellectual depth are inextricably linked within the philosophy of science. I was fortunate enough to attend a class given by Georges Canguilhem at the very end of his career, but I was not one of his students in the classic sense of the term: Canguilhem was not my thesis advisor. He certainly facilitated my career, for which I am grateful; however, his primary role was as an intellectual model, an example hard-wired into my own mentality. In this sense, Georges Canguilhem truly was my "master".

Like Knowledge of Life, the present work is that of a philosopher, meditating on fascinating themes from the domains of biological and medical sciences. My work has developed within a type of triangle, with philosophy, science (notably biology) and the history of science at its points. I have been in constant contact with contemporary scientific advances, perhaps to a greater extent than my master; I have also been more deeply involved in the history of science from a "professional" perspective, delving into both written and oral archives. Furthermore, in my work I attended to the philosophy of science at the international level. I hope that my work was no less philosophical than his, but in this respect readers may form their own opinions. My approach to philosophy is more specific in the sense that it is rooted in a particular scientific context, and less in general philosophy and the history of philosophy than that of Canguilhem. Contemporary evolutionary biology, genetics, quantitative methods (notably probability and statistics) have all captured my attention, mostly from a theoretical point of view, but I have also made occasional forays into the practical sphere.

Like Knowledge of Life, this book is kaleidoscopic. There is no single or dominant central theme. Instead, my work is organized around a method, applied to a certain number of questions relating to biology and its history. Few, if any, scientific domains have undergone such an incredible renewal over the last century. Unlike Canguilhem, I have refrained from assembling previously-published texts: the reflections in this book are the result of a series of interviews with a young philosopher.

The history and format of this book go hand-in-hand. In 2010, Victor Petit, who had just completed his philosophy thesis on the history of the concept of milieu, approached me with the idea of producing a book of interviews. We did not know each other at the time. We began recording; weeks turned into months and months turned into years - three, in all, following a structure thought out by Victor. From the outset, I decided not to discuss the overall structure of the work or the questions being asked: this book is therefore as much a reflection of Victor Petit's perception of my work than of my own perceptions. Victor was able to identify some fundamental questions present in my work, both those I tackled explicitly and those which had always remained implicit, without formulation or justification. For me, these interviews took the form of an in-depth, and sometimes painful, examination of conscience. Victor Petit also asked me a number of questions which are crucial to the philosophy of biology, but which did not relate directly to any given aspect of my existing work. Whilst these questions sometimes took me outside of my comfort zone, in terms of both skills and interests, I responded to them to the best of my ability. This is one of the reasons the book took so long to "mature".

Another, purely personal, factor also delayed the completion of this work, which is far larger than we initially anticipated. Victor carefully transcribed all of my oral responses; seeing the results, I was somewhat taken aback. Whilst he was content with my answers, pushing me to provide a more detailed, committed response to those questions which he considered to be most critical, I was horrified to see what I had said, and the way in which I had said it, in writing. This phenomenon appears to be a common feature of this type of editorial experience. I continued to prevaricate, never quite satisfied with the minor stylistic modifications which I had made here and there. Then, a few months before the book was due to be published, came the crucial moment when I was able to pinpoint the reason for my inhibitions, delaying what should have been a gratifying experience. As I told Victor in late 2016, I was struck, at one point, by the impression that in spite of my deep introversion, I was not particularly interested in myself. This observation, doubtless somewhat exaggerated, may well have surfaced during a period of personal "reconfiguration" - the upheaval which came after I was diagnosed with a terminal illness. In any case, this revelation, in conjunction with my sentiment of culpability regarding the delay which I had imposed on my partner and, truth be told, the fact that the ultimate deadline was looming, gave me the impetus to bring the project to its conclusion. Victor and I established one simple rule: without tampering with the foundations of the book, I would revise and develop my answers at a rate and in a style of my choosing. I therefore edited all of my contributions, attempting to preserve the spontaneity of my responses whilst doing what I know best: explaining, justifying, and supporting my statements. I know that Victor was not convinced by this approach; he wished to retain many of the asides, the elements of uncertainty and the excesses present in our verbal exchanges. However, given that I am neither a political nor a cultural celebrity, I did not feel this to be appropriate. I am a professor, and I work with concepts; my feelings, excesses, and linguistic weaknesses are of no interest to anyone. For a man or woman of action - politician, artist, or other - the real-world conditions in which an act occurs are significant. Their immediate, on-the-spot reactions are revealing, and media interest in these reactions is both legitimate and understandable. In my case, however, the spontaneous aspect would have been of little interest. Victor Petit gleaned what he could - a considerable amount, in fact. At the end of the day, though, I preferred to take a step back. I have attempted to separate the ideas from the author, as far as is reasonable in the context of a series of interviews.

I learned a lot through working with Victor Petit. The process was a form of intellectual communion - amicable and courteous, but demanding at the same time, with regard to both Victor's questions and my responses. This is the reason why our interview, originally destined for publication six or seven years ago shortly after the end of our discussions, evolved over time into a whole book. I have attempted to clarify my intellectual stances, to explain concepts - some rather difficult to grasp, either philosophically or scientifically - in as simple a way as possible, and to respond to new questions which emerged. This weighty volume of discussions might be considered as a foreword to the rest of my work, but I very much doubt that any publisher would accept a "foreword" of this type. In a way, it is both less than and more than a foreword: less, as it makes no pretensions to exhaustivity; more, as it often goes further than my previous writings, and because it is the result of a collaborative effort. Over the course of my career, I have written over 40 forewords - I even, at one point, considered writing a book on "the art of writing forewords". Evidently, this book is not a foreword; instead, it is an after-word, the work of one looking back over his previous writings.

Each chapter in this book is designed to be read independently, and each covers one of the four main dimensions of my work. I am thankful to Victor for clearly identifying these dimensions. They do not cover all of my work, but all of the essential themes and guiding principles are present. Chapters 2 and 3 ("Darwin and Darwinism" and "Genetics") relate to the domains on which most of my work has focused; these are the subjects with which I am most comfortable. The first chapter ("Philosophy of Biology") concerns a discipline which I first encountered relatively late in my career, through increasingly frequent visits to North America. I was, I believe, the first to introduce this domain of philosophy in the French university system, in the late 1990s. I learned more about the subject as I taught it, and a body of work has slowly grown out of the domain. Nevertheless, the philosophy of biology was never my primary area of study, coming after classical philosophy, biology, and the philosophical history of science. The final chapter in this book relates to social questions raised by the life sciences at the time of writing (eugenics, race, human evolution,...