Knowledge of Life Today: Conversations on Biology (Jean Gayon interviewed by Victor Petit)

By Jean Gayon and Victor Petit

Knowledge of Life Today presents the thoughts of Jean Gayon, a major philosopher of science in France who is recognized across the Atlantic, especially for his work in philosophy and the history of life sciences. The book is structured around Gayon's personal answers to questions put forward by Victor Petit. This approach combines scientific rigor and risk-taking in answers that go back to the fundamentals of the subject.

As well as the relationship between philosophy and the history of science, Gayon discusses the main questions of the history and philosophy of biology that marked his intellectual journey: Darwin, evolutionary biology, genetics and molecular biology, human evolution, and various aspects of the relationship between biology and society in contemporary times (racism, eugenics, biotechnology, biomedicine, etc.).

• Language: English
• Publisher: Wiley
• Release date: Apr 10, 2019
• ISBN: 9781119610489

Book preview

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, biotechnologies etc.). I have only begun to consider these issues relatively recently, and always in response to social demands; my intellectual inclination is to avoid man. I have no regrets in this respect; the questions tackled in this chapter are of primary social and cultural, as well as scientific, importance to the modern world.

Thanks are due firstly to Elisabeth Valsecchi Gayon, who read and re-read the manuscript until it was actually readable. Françoise Parot read through all of the previous versions of the text, and insisted that I keep working on it until I was totally at ease with what had been said. Armand de Ricqlès, Mathilde Lequin, Frédéric Bouchard, Pierre-Henri Gouyon and Michel Fichant all made valuable suggestions concerning particular developments. There are many references to my own works in this book. For reasons of clarity, the following notation has been used: books are noted JG, followed by roman numerals (e.g. JGXXIV); articles and chapters in compilations are noted JG followed by Arabic numerals (e.g. JG292). Full details may be found in the References at the end of the book. However, this book is by no means intended as an inventory; instead, it should be seen as a form of meditation following the inventory.

Jean GAYON

February 28th, 2018

1 CANGUILHEM G., La connaissance de la vie, Paris, Hachette, 1952. Second edition, Paris, Vrin, 1965. English translation, G. CANGUILHEM, Knowledge of Life, trans. by Stefanos Geroulanos and Daniela Ginsburg, Introduction by Paola Marrati and Todd Meyers, New York, Fordham University Press, 2008 [1965].

Introduction by Victor Petit

It is a universal truth that the most talented individuals are also often the most modest. It is equally the case that the most modest individuals are rarely the best-known. Jean Gayon is a prime example of this; extremely modest, he has only truly achieved international recognition for his contributions within one particular academic field. Hopefully, this book will contribute to introducing his scholarship to a wider readership.

Anyone who knew Jean Gayon will tell you that he was both a historian and a philosopher, of science in general and of biology in particular. The development of the philosophy of biology as a field in its own right, particularly in France but also elsewhere, and this is mainly the result of Jean’s efforts. Scholarly work is not only measured in terms of writings; a scholar’s influence as teacher, thesis advisor¹, organizer, and academic and intellectual partner is also crucial. Having been present at a symposium held in honor of Jean Gayon very recently², I am in no doubt as to the strength and effectiveness of his influence.

I believe that the best way to exemplify our modern understanding lies in an extensive analysis of Darwin’s basic logical commitments, the reasons for his choices, and the subsequent manner in which these aspects of ‘the structure of evolutionary theory’ have established and motivated all our major debates and substantial changes since Darwin’s original publication in 1859³. These words are drawn from Stephen Jay Gould’s introduction to his seminal work on evolutionary theory, but they equally reflect Jean Gayon’s approach, as seen for example in his work on the Darwin/Wallace debate. For both Gould and Gayon, an examination of the historical background was essential to understanding current scientific work in evolutionary biology.

Jean Gayon’s first major publication was his doctoral thesis, which appeared in French in 1992 (Kimé) and in English in a revised and updated version in 1998 (Cambridge University Press). During his career, he edited a number of collective works, notably papers presented at a conference held in Dijon, France, in 1988 to mark the 200th anniversary of Buffon’s death (JG IV) where, six years before, Gould debated his theory of punctuated equilibrium⁴. Gayon was also partly responsible for the publication of a multidisciplinary book on the notion of form (JG V), which he edited in collaboration with the philosopher Jean-Jacques Wunenburger. The pair would go on to work together on two other occasions (JG VII, XI). Over the period ranging from 1992 to the present, Jean Gayon has published over 300 articles, books, and other writings. This impressive bibliography, covering a variety of subjects, from rhetoric to the teaching of philosophy in US universities, via reflections on color and on monsters, is listed at the end of this book. It would not be possible to cover all of these subjects in a single volume; I instead chose to focus on Jean Gayon’s main areas of interest and expertise, namely the philosophy of biology and the general philosophy of science. Even a cursory look at his work clearly shows that the philosophy of biology, following the approach set out by Canguilhem, must necessarily involve a historical approach. Indeed, some of the most important epistemological questions addressed in Jean Gayon’s thesis were historically motivated, beginning with the fundamental observation that Darwin never actually spoke of natural selection as a fact, whether in On the Origin of Species or elsewhere (JG I, p. 9). In that case, then, what did Darwin actually prove? In his thesis, Gayon examined the hypothesis of natural selection in relation to the problem of heredity in biometrics and population genetics. His historical analysis shows that the explanatory power of natural selection, as set out in Darwin’s seminal work (1859), was not fully established until 70 years after its publication.

Jean Gayon’s career as a published author may have begun in 1992, but his scholarly work started in 1984 with a hundred-page document written for the CNRS (Centre National de Recherche Scientifique / National Center for Scientific Research) and entitled Histoire et épistémologie de la théorie synthétique de l’évolution (1930–1950) / History and Epistemology of the Synthetic Theory of Evolution (1930–1950)⁵. The second paragraph began with the following statement: It would not be absurd to consider my work to be completed once I succeed in clearly identifying its subject matter⁶. This theme, which is both historical and epistemological, and to which Gayon later returned⁷, was central to the author’s overall contributions to the history and philosophy of biology. In France, he is the undisputed expert on the so-called synthetic theory in the history of the life sciences. Since its inception and its foundation in population genetics, the modern evolutionary synthesis was continuously renewed, as it went on to include disciplines such as developmental biology and ecology. Jean Gayon was especially fascinated with the potential for scientific theories to undergo a complete transformation whilst retaining their conceptual identity, a phenomenon he called the commensurability paradox (JG I, p. 411): for instance, evolutionary biology was clearly established by Darwin, but Darwin’s own hypothesis has been completely rethought, from start to finish, resulting in what we now know as the theory of evolution. It is difficult to say exactly what the theory of evolution, or indeed Darwinism, means today or in the past. One thing is clear, however: the principle of natural selection has continued to occupy a central place in evolutionary biology, despite the many changes undergone by the theoretical framework. How could one fail to be enthralled by the vast gap between the paucity of the logical foundation of the principle of natural selection and the richness of its explanatory power?

Jean Gayon did not only consider evolutionary theory from a historical standpoint: he also looked at it from a philosophical point of view. Like Marjorie Grene before him⁸, he believed that the theory of evolution had significant implications for philosophy and its most fundamental questions, namely: 1) what can I know?, 2) what must I do?, 3) what may I hope for?, 4) what is man?⁹. To say that Jean Gayon is Darwinian is not only to say that he is an expert on the works of Darwin and his readers; it also implies that he thinks like an evolutionist. Evolutionary thought applies as much to concepts as to living beings, and it is perfectly pertinent for the philosopher to adopt Darwin’s view that Our classifications will come to be, as far as they can be so made, genealogies¹⁰.

Knowledge of Life: the roots of a project

In 1947, Canguilhem only had two allies in his defense of biological philosophy in France, Henri Bergson and Raymond Ruyer¹¹. Georges Canguilhem was the director of the IHPST (Institut d’Histoire et de Philosophie des Sciences et des Techniques / Institute for the History and Philosophy of Science and Technology) from 1955 to 1971; Jean Gayon held the same post from 2010 to 2016. The situation of the philosophy of biology underwent significant evolutions in the intervening period.

Philosophy is a subject which thrives on the unknown, and one might even say that it requires the unknown in order to thrive¹². One of the best-known quotations from Canguilhem’s writings, this statement is particularly evocative when speaking of Jean Gayon’s work. Following Canguilhem’s advice, he set aside philosophy to concentrate on science, before returning to a different philosophy, once transformed by science. Jean Gayon has only, and very recently, made one other contribution written in the first person; in this (JG 260, pp. 205–206), he stated that Since then, I have only been able to apply my limited philosophical talents (in exegesis, analysis, and systematicity) to subject matters which were not specifically philosophical in nature. Jean Gayon’s philosophical approach, like that of many of his contemporaries, was motivated by a search for truth, which cannot be attained through words alone (JG 260, p. 205). His passion for scientific activity was thus part and parcel of his philosophical contributions.

Canguilhem’s Knowledge of Life is a collection of seven essays written between 1945 and 1962. It is significant that the general philosophical context at the time of publication tended to impose a dichotomy between thought-world and life-world¹³. This seminal collection of texts lays out the key concepts used by Canguilhem, beginning with the inseparability of the individual organism and their milieu. For Canguilhem, biological individuality was not simply a term, but also and foremost a constitutive and normative relation between an organism and its surrounding: in this respect, it would be wrong to consider individuality as something limited to the boundaries of a cell, an organ, or even an organism. In fact, Jean Gayon has written very little about the man he considered to be his master, with the exception of a single article on Canguilhem’s concept of individuality (JG 79, 100). I shall not go into detail with regard to his analyses here. Note, simply, that the notion of individuality put forward by Canguilhem and used by today’s philosophers of biology, such as Thomas Pradeu, are different. There is, however, some continuity between the two since Jean Gayon was the student of the former and thesis adviser of the latter. Still, the context to discuss notions such as biological individuality, on every other philosophical issue, has changed; today, philosophers draw their inspiration from the works of American philosophers, such as David Hull, rather than from German biologists, such as von Uexküll and Goldstein. In the final phrase of his preface to the first edition of Knowledge of Life (1952), Georges Canguilhem observed: "We have made every attempt to merit the title of the collection [Science and Thought] in which this brief work [Knowledge of Life] will be published, using and providing the most precise information possible, and striving to maintain a distinction between the philosophical themes addressed here and our elucidation of these themes". Jean Gayon, too, has always been careful to use and provide the most precise information possible, and this precision is one of the defining qualities of his work: the author’s erudition, rigor, and attention to detail have been recognized by all those who know him or his writings. However, Canguilhem’s influence went far beyond his role as a paragon of academic excellence, and was especially perceptible in his work within the IHPST. His reach also extends beyond the specific domain of the life sciences, affecting the very meaning of philosophy in terms of its relation to science, fostering a convergence between science and philosophy, whilst continuing to see them as distinct and autonomous academic fields. He also bridged the philosophical gulf which had developed between knowledge and life, re-establishing strong links between the two and, in this case, refuting their independence.

Is Jean Gayon, then, a Canguilhemian? To fully address this question, one must first clarify what is meant by Canguilhemian; however, I shall not go into detail on the subject here. From my point of view, Canguilhem’s reconciliation between knowledge and life does not appear to take the same form in Jean Gayon’s work. Canguilhem’s rationalist vitalism, to borrow a phrase from François Dagognet [DAG 85] and taken up by Paul Rabinow [RAB 94], is not part of Gayon’s philosophical DNA. Perceptive readers may have noted that my probing questions on the definition of a living entity in relation to its milieu were my way of testing the depth of Jean Gayon’s Canguilhemian ideas. Although Gayon is not a vital rationalist, he is without a doubt a reasonable rationalist such as those described by Canguilhem in the introduction to his book¹⁴. His ideas can probably not, therefore, be described as Canguilhemian. Jean Gayon’s methodology, however, is closer to the one used by Canguilhem, as we shall see later in this book. To paraphrase a statement made by Gayon himself, his work is an extension of Canguilhem’s methods, rather than an expansion of his concepts¹⁵.

If this book, Knowledge of Life Today, is indebted to Knowledge of Life, then it is in the form of a disciplinary legacy: a method, rather than the content, or, better still, a certain "style¹⁶; the two works are very different in terms of their origins, format, and purpose. Canguilhem insisted that the history of science must be assembled scientifically in order to be used philosophically¹⁷. Jean Gayon’s PhD thesis was in both the history and the philosophy of science. The historical aspect lies in the fact that nothing can ever guarantee a priori that any given aspect of the history of science may be reconstructed in a rational manner. In turn, its philosophical dimension relates to the claim that the primary aim of science is to solve problems for which a rational solution may be found, i.e. [problems] which are not specifically linked to the particular historical conditions in which they were encountered" (JG I, p.6). This book may be seen as a defense of the History and Philosophy of Science (HPS), or, more precisely, as a reminder, at a time when science studies tend to focus most intently on specific historical conditions.

Origins and structure

Allow me to speak of my own experience for a moment (perhaps some of Jean Gayon’s natural authority has rubbed off on me). In writing this introduction, I have experienced something of a crisis of legitimacy. Of all of the young philosophers surrounding Jean Gayon, I am probably the least fitted to write about his legacy. I was never his student, I came to the philosophy of biology as an outsider, and my contacts with the IHPST have been rather limited. My inherent timidity in this regard would never have allowed me to undertake a project of this type, had I not met Jean Gayon in a family context. The impetus and the courage needed to launch this project thus came from an exceptionally favorable situation, rather than from my own nature or nurture! Several years on, it is an immense privilege to be writing the introduction to this book.

When I first met Jean Gayon, I had just defended my doctoral thesis, which was supervised by Dominique Lecourt, another proponent of the same tradition within the French HPS world. Although I did not know Jean personally, I was well aware of his work; at the time of our meeting, I was particularly interested in the philosophy of biology, and it is impossible to go far in this field without encountering Jean Gayon’s writings: every article I found served as a point of reference. Jean Gayon’s bibliography demonstrates that he left few stones unturned within his domain¹⁸.

When approaching Jean Gayon with my proposed project, my main aim was to create a single-volume compendium of some of the results of his research, which were then scattered across several different books and articles, in order to make his work more accessible. I wished to bring together key moments in the history and philosophy of biology within a single book, produced with a wider, less specialist audience in mind. I also wanted to find out what Jean thought about certain subjects not covered in his work, including a number of more polemical and political topics. I was not particularly successful in this regard: firstly, due to Jean Gayon’s modesty and reluctance to state an opinion on matters which he felt he did not perfectly understand, and secondly, as he had no wish to enter into polemical debates, preferring to maintain an outsider’s view. In retrospect, I think that I may also have been motivated by the fact that this work offered the opportunity for me to enjoy what were effectively private lessons from Jean Gayon. Evidently, our interactions took the form of interviews, rather than lectures; but readers will notice that my questions were often of the type which a student may ask of a teacher, sometimes rather naïve, and always probing. The answers I received were those of a master in his field, often bold, always precise. This book could be seen as a form of professional legacy: as Jean Gayon was entering retirement, the words contained in these pages will continue to echo his voice as a great teacher.

As we have seen, I have very little claim to legitimacy in Jean Gayon’s field of expertise. However, this was not necessarily a hindrance. The formulations of my questions may well reflect the spontaneity present in the minds of non-specialist readers: they were general, candid questions about the meaning of the concepts of law, life, gene, or "homo". All of the questions presented in the following were asked and answered verbally over the course of my interviews with Jean Gayon, although some have been shortened or split into separate parts. As can be seen from the fact that some responses run to multiple pages, Jean Gayon completed and improved the transcripts of his oral responses, often extending and specifying his answers without ever changing their essential substance. I tried, as far as possible, to stay in the background when posing questions. Some of the author’s responses are extremely technical, but as a whole, we felt that this book met our aims, namely: remaining accessible to non-specialist readers without sacrificing historical precision and philosophical nuance.

The discussion of the history and philosophy of biology is split into four large chapters. The first consists of general epistemological questions and of an investigation of works by philosophers interested in biology. The next two chapters go deeper into the philosophy of biology by means of two historical studies, one on Darwin (and Darwinism) and one on genetics (Mendelian and molecular). The section on the history of genetics ends by touching on the historical subject which Jean Gayon has studied in greatest depth: the history of genetics in France. Evidently, this historical approach does not exclude philosophical aspects, and we see that Darwin’s statements concerning species might equally be applied to genes: no one definition has satisfied all biologists; yet every biologist knows vaguely what he means when he speaks of a gene¹⁹. The fourth and final chapter concerns those questions raised by Jean Gayon’s work which specifically pertain to societal debates. These questions were approached from a philosophical perspective: for example, how are we to approach the common but divisive distinctions between innate and acquired, nature and nurture, heredity and environment, which have yet to be clearly defined in scientific terms? Note, too, that Jean Gayon does not approach eugenics, race and human augmentation as a historian of ideas, but rather as a historian of science.

The questions contained within this work have been deliberately organized so that it may be treated as a textbook. Each section can be read independently of the others, and yet, as within the whole of Jean Gayon’s work, there is a remarkable degree of continuity. Starting with the history of science, and notably Darwin, the book ends with a discussion of the future of medicine and a brief look at the problem of transhumanism. One definition of transhumanism is as an attempt to take control of the evolutionary process, which brings us back to the starting point, the principle of selection, that magician’s wand, by means of which he may summon into life whatever form and mold he pleases²⁰.

This introduction would not be complete without evoking the pleasure I derived from these interviews and the great honor Jean Gayon bestowed upon me by agreeing to the project. The author’s scholarly standard and open-mindedness are undisputed. Over and over again, others have noted his precision, modesty, courtesy and consideration. I have found his attention to detail to be particularly striking. Throughout the hours of interviews, at his home on Rue de Vaugirard or in his office on Rue du Four, I came to appreciate just how much care Jean Gayon takes over everything he does. He is extremely precise in his use of words and language, careful to specify his references and justify his statements. He also pays great attention to those to whom he speaks. His manner of speaking, simply and unassumingly, is a balm for restless spirits like my own.

I have many, many more questions to ask Jean Gayon.

Victor PETIT

⁂

This introduction was written prior to Jean Gayon’s death on April 28th, 2018. I was obliged to look over the proofs without him – without my friend and mentor. I thus carry the responsibility for any errors which may remain.

Homages have flooded in from all quarters, both within France and from other countries. I shall not add my own here: the weight of grief still hangs heavy, and it is too early for me to clearly understand what a great man we have lost – a man of great rigor but without severity, kind but honest (as Christian Godin put it in his obituary for the journal Cités). This book bears the imprint of his moral qualities, for example in the way in which he chose to highlight the work of his students and colleagues instead of his own efforts.

Jean Gayon’s final action as an intellectual was to answer the last question in this book; by that point, his pain was almost unbearable. When I first asked it, he was still involved in a number of important projects. At my insistence – and probably also out of vital necessity – what was initially a paragraph expanded to fill 10 pages. This last answer was formulated eight years after I asked my first question, following years of long and patient work. In it, Jean Gayon speaks in the first person, whilst avoiding speaking of himself, something which he detested. In this, his final work, he wrote as a philosopher, discussing the importance of friendship (in relation to wisdom) and courage (in philosophical terms) in his life, not just in his teaching; Jean died, as he lived, as a philosopher. I clearly remember the joy with which he spoke of re-discovering Plato and Horace in the context of the final question in this book – Jean Gayon’s testament, if you will – hence my decision to mention this particular response here. A life-long learner, he seemed to have rediscovered the joy of a student discovering something new, finally agreeing to write on a subject outside of his usual areas of expertise. I hope that readers will sense this joy shining through the text: not that of a life devoted to knowledge alone, but that of knowledge devoted to life. It is also possible to sense Jean Gayon’s debt to his master, Georges Canguilhem, as much in the man himself as in his work. Finally, it is my dearest wish that this book should give a glimpse into Jean Gayon’s exemplary life, of his courage, above and beyond the undisputed intellectual value of his written legacy.

1 Seven of Jean Gayon’s former doctoral students have received the prestigious Prix de la Chancellerie des universités de Paris.

2 Philosophie, histoire, biologie. Journées scientifiques en l’honneur de Jean Gayon, March 15–16, 2017, ENS-Paris. See Francesca Merlin, Philippe Huneman (eds), Philosophie, histoire, biologie. Mélanges offerts à Jean Gayon, Paris, Éd. Matériologiques, 2018.

3 GOULD S.J., The Structure of Evolutionary Theory, Harvard University Press, Harvard, 2002.

4 Papers from the 1982 conference were published in J. CHALINE (ed.), Modalités, rythmes et mécanismes de l’Evolution biologique : Gradualisme phylétique ou équilibres ponctués ? (Dijon, May 10–14, 1982), Éd. du CNRS, Paris, 1983. Cf the dedication of Stephen Jay Gould’s final book, cited above.

5 GAYON J., Project and program of work presented to the philosophy, epistemology and history of science commission of the CNRS: Histoire et épistémologie de la théorie synthétique de l’Evolution (1930–1950), 1984. Thanks to Jean Gayon for giving me access to this document.

6 Ibid., p. 3

7 Notably in the context of an IHPST research program, the subject of a forthcoming special edition of the Journal of History of Biology, entitled Revisiting the Modern Synthesis, directed by Philippe Huneman (with a contribution by Jean Gayon).

8 GRENE M., A Philosophical Testament, Chicago and La Salle (Ill.), Open Court, pp. 107–112, 1995.

9 KANT I., Logic, trans. R. Hartman and W. Schwarz, Dover Editions, New York, 1988.

10 DARWIN C., On the Origin of Species, London, 1859.

11 CANGUILHEM G., Notes sur la situation faite en France à la philosophie biologique, 1947, Œuvres Complètes, vol. IV, Vrin, Paris, pp. 307–320, 2015.

12 CANGUILHEM G., Le Normal et le Pathologique, Paris, 1966. An English edition exists – The Normal and the Pathological, trans. C. Fawcett, New York, Zone, p. 33, 1991 – although the translation of the phrase above is our own.

13 This opposition was notably expressed by Husserl, most clearly in Philosophy and the Crisis of European Man, a lecture given in Vienna in 1935. The notion that the world of life and the world of science were incompatible was not limited to the realm of phenomenology; the same idea was expressed by Bachelard in his Philosophie du non (1940), in Arendt’s The Human Condition (1958), and, in a slightly different form, by Koyré in Newtonian Studies (1965).

14 For our part, we think that a reasonable rationalism must know how to recognize its limits and to integrate the conditions of its practice (CANGUILHEM G., Thought and the Living, in Knowledge of Life, trans. S. Geroulanos and D. Ginsburg, FUP, New York, 2008).

15 Jean Gayon, following Stephen Jay Gould, made a distinction between the extension and the expansion of Darwinism. Extension consists of broadening the field of application, both within and outside of the field of biology; expansion consists of a deeper investigation of basic ideas, and can result in significant modifications. Both the extension and the expansion of Darwinism will be discussed here.

16 It would be tempting to apply Jean Gayon’s remarks on style in the sciences (JG 57, 75, 97) to the history of science too.

17 CANGUILHEM G., Rôle de l’histoire des sciences dans la philosophie des sciences : l’établissement des faits fondamentaux de la dynamique (1949), Œuvres complètes, vol. IV, Vrin, Paris, p. 390, 2011.

18 The following list covers Jean Gayon’s principal contributions to the philosophy of biology. These philosophical studies often comprise a historical component. However, we have chosen to omit publications relating specifically to the history of science. Unfortunately, we were unable to touch on all of Jean Gayon’s areas of interest within the context of this work.

Philosophy of biology: JG X, 200, 207, 263, 287.

Laws in biology: JG 22, 150, 161, 265, 289.

Realism and naturalism in biology: JG 23, 131, 137.

Definition of life: JG XVIII, 222.

Vitalism: JG 33, 229.

Functions: JG XIX, 163, 190, 193, 215, 227, 250.

Evolution, evolutionism, Darwinism: JG 5, 10, 14, 15, 27, 29, 30, 31, 45, 63, 74, 80, 86, 159, 196, 201, 214, 220, 224, 230, 231, 261, 273.

Metaphysical implications of the theory of evolution: JG 113, 152.

Selection (natural, sexual, artificial), fitness: JG I, II, 5, 32, 39, 41, 61, 68, 90, 213, 224, 245. Heredity, genetics, molecular biology: JG VII, XII, XXI, 15, 26, 46, 64, 76, 104, 112, 170, 186, 205, 233, 270, 285.

Biological individuality: JG 18, 49, 79, 176, 196, 221.

Form and evolution: JG V, 14, 30, 80.

Species: JG 14, 18, 196, 248.

Chance and evolution: JG 31, 62, 159, 160, 239.

Sex: JG 83.

Model organisms: JG 167.

Monsters and monstrosity: JG 141, 144.

Cultural evolution: JG 153, 155.

Biodiversity: JG 154, 154bis, 259.

Evolution and psychology: JG 16, 20, 181, 193.

Evolution and economics: JG 83, 98, 217, 236, 257.

Epistemology of medicine: JG 132, 164.

Eugenics: JG XI, 19, 21, 65, 71, 88, 114, 169, 246, 257.

Notion of race: JG 66, 116, 117, 129, 149, 189, 191, 195.

Human improvement, animal improvement: JG XII, XXIII, 234, 251, 264, 275.

Philosophy and biology, key figures: Darwin (JG 86, 228), Bergson (JG 145, 184, 198), Bernard (JG 59, 175), Canguilhem (JG 79, 100), Cournot (JG 161), Grene (JG XV, 218), Monod (JG 233), Pearson (JG 180), Piaget (JG 7, 20, 193), Nietzsche (JG 81, 82, 105, 106), Popper (JG 232), Ruyer (JG 44), Sober (JG 5, 261), Wallace (JG 228, 238, 243).

19 No one definition has satisfied all naturalists; yet every naturalist knows vaguely what he means when he speaks of a species (Darwin, op. cit., C.2, p.77).

20 A citation from William Youatt (1837), a London veterinarian, given by Darwin, op. cit., C.1, p. 65.

1

Philosophy of Biology

As a philosophy student, prior to discovering your work, I thought that the philosophy of biology began and ended with Canguilhem. You introduced this field of research in France. Before going into detail concerning the concepts involved, I’d like to know what the philosophy of biology is not, to cite the title of David Hull’s famous article¹.

The philosophy of biology was not a new concept at the time Hull was writing, in the late 1960s. The expression was first used in English by William Whewell in 1850, and cropped up periodically, taking a variety of interchangeable forms such as biological philosophy or philosophy of the life sciences. In French, philosophy of biology was rarely encountered prior to the 1980s; philosophie biologique (biological philosophy), philosophie des sciences de la vie (philosophy of the life sciences) or "épistémologie des sciences de la vie (epistemology of life sciences) were used from time to time. David Hull’s article, What the philosophy of biology is not", was an act of rebellion by its author against the way in which philosophers of science of the analytical tradition and/or neo-positivist philosophers approached the biological sciences. In 1969, David Hull was 34. His 1969 manifesto (for it was a manifesto) was his eighth publication; the author’s first work was published in 1964. Hull objected to the non-critical application of concepts and methods inspired by ahistorical and general analyses of scientific discourse, which were themselves implicitly rooted in physical theories. For example, Hull lampooned the attempts made by Joseph Henry Woodger (1894–1981)², an English philosopher, to axiomatize biological theories, particularly in the field of genetics. Hull felt that this type of activity was inherently sterile, having no effect on real scientific practices. Karl Popper’s reflections on refutability and parsimony, on the other hand, had a considerable impact on a number of scientific domains, particularly in the cladistic branch of biology. Hull thus called for philosophers with an interest in biology to interact directly with biologists themselves, addressing methodological issues alongside more pointed questions relating to specific scientific content and rooted in areas of actual research.

Collaborative work of this type did, in fact, begin to take shape from the 1970s onwards. A number of individuals began to define themselves as philosophers of biology, breaking away somewhat from a more general philosophy of science to focus on the concepts, theories and methods involved in contemporary biology. This development was not solely a response to David Hull’s exhortations. Figures such as Marjorie Grene, Michael Ruse and others, some of whom are mentioned in Hull’s 1969 article, had already begun work in this area. However, Hull’s article had a significant impact in lexical terms. Prior to 1970, the terms philosophy of biology, biological philosophy and philosophy of the life sciences were used interchangeably. Following on from What the philosophy of biology is not – which could just have well been called "What the philosophy of biology should be" – the expression philosophy of biology became the banner beneath which the domain’s supporters came together, aiming to establish a field of philosophical reflection in direct relation to applied biological research.

At this juncture, I would like to note that the emergence of the philosophy of biology, as a separate sub-discipline within the philosophy of science, resonates, in some ways, with a similar development which took place in the history of science during the same period. The new history of science fought back against the perceived dominance of abstract philosophical models, calling for a new focus on science in action, as in the philosophy of biology. The development of disciplinespecific philosophies of science over the last four decades has largely focused on an increased integration with actual science.

1.1. The philosophy of biology

1.1.1. Laws in physics and biology

As a philosopher of biology, you have obviously considered the scientific specificity of biology. In your article "La biologie entre loi et histoire (Biology, from laws to history)"³, you spoke of biology as a science without laws. What do you mean by this?

Philosophers more or less universally agree that biology, and evolutionary biology in particular, has presented significant challenges to a number of traditional concepts in the general philosophy of science, including the notion of natural law, at least in terms of its application to the life sciences.

The statement that there are no laws in biology refers to the concept of law promulgated by the neopositivist philosophers of science (particularly Carl Hempel and Ernest Nagel). For the neopositivits, laws are empirically true statements with a universal logical form. However, this formulation is insufficient, as, applied in its strictest sense, it implies that all accidental generalizations (e.g. all of the coins in my pocket are one-euro coins, a phrase which has the logical form of a universal statement) are laws, which would be absurd. It was therefore necessary to clarify that enigmatic property of the laws of nature which philosophers, starting with David Hume in the 18th Century, referred to as natural necessity. The result was the formulation according to which a law is a statement of unlimited universal scope, that is containing no spatio-temporal limitations, whether explicit or implicit. Nelson Goodman⁴ modified this formulation by adding a modal criterion. For Goodman, a nomological statement is a statement which supports (i.e. justifies or permits) counterfactual statements, that is statements which are contrary to fact. For example, when we say that sugar is water-soluble, we implicitly accept the following counter-factual statement: "if I put this sugar cube in my cup of coffee, it would dissolve". The two propositions in this phrase are counterfactual, as the specific sugar cube involved in our thought experience is not in my coffee, and is therefore not dissolved hic et nunc in this world. The strength of a nomological statement lies precisely in the fact that it is not only valid in this world, but in any other possible world resulting from a different sequence of events and obeying the same laws. Thought experiments based on counterfactuals offer a powerful tool for identifying generalizations which are not laws but are simply accidental, that is de facto generalizations limited to a particular portion of space and time. Returning to the example of the coins, the phrase all of the coins in my purse are one-euro coins does not allow us to infer that "if this ten-cent piece in my hand were in my pocket, it would be (or would become) a one-euro coin".

Nelson Goodman developed a linguistic criterion which is remarkably effective in detecting statements which take the form of universal logic, but which are inextricably linked to particular temporal conditions (i.e. accidental generalizations). This proposal has attracted considerable attention within the field of philosophy. It has been criticized on the grounds that the notion of possible worlds it uses is too vague. David Lewis suggested a more restrictive formula, according to which universal statements which are empirically true may only be considered to be laws if they are true in all nomologically-accessible worlds⁵. The restriction to nomologically-accessible worlds excludes possible worlds governed by laws which are completely different to those which we know, or non-nomological worlds, that is worlds without order.

This modern understanding of the laws of nature is easy to apply in the field of physics, but problematic in biology. Within the life sciences, it is hard to find generalizations with unlimited universal scope. Most biological generalizations appear to be limited to a small portion of the history of the universe, that corresponding to the history of life on our planet.

As far back as the 19th Century, the French philosopher and mathematician Antoine-Augustin Cournot noted that the life sciences are faced with collections of singular entities (species), each of which appears to be governed by its own laws. According to Cournot, instead of universal laws, each species seemed to be subject to unique decrees, the result of coups d’État, which the author compared to Napoleon’s coup of 18 Brumaire, a historical event. In biology, therefore, there are no (timeless) laws, but rather a series of unique decrees, each resulting from a coup d’État⁶.

But the term laws is still used in biology. Is a term such as "Mendel’s laws" still epistemologically relevant?

Not if we understand the concept of laws in the way I just described. Lewis’ criterion may be usefully applied in determining whether or not Mendel’s laws are genuine laws of nature⁷. The reason Mendel’s laws cannot be considered to be genuine in the same way as Newton, Maxwell or Einstein’s laws is that it is possible to imagine worlds governed by the same laws (i.e. all existing laws with the exception of Mendel’s) in which Mendel’s laws would not be respected. For example, there is nothing to prevent us from imagining that sexually reproducing animals may have evolved on an exoplanet, independently of the history of life on Earth. These animals would exist in a physical environment obeying the same laws found on Earth and throughout the whole universe, and would also be structurally and functionally similar to terrestrial animals; for example, they would be made up of macromolecules such as nucleic acids, proteins and carbohydrates. They would have an articulated internal skeleton and would share many physiological properties with animals on earth. However, meiosis, that is the mode of division which produces haploid gametes (n chromosomes) from diploid cells (2n chromosomes) would not work in the same way, and might involve a mechanism used to eliminate all gametes except for a certain type⁸. In this case, Mendel’s first law – relating to the independent segregation of genes – would not apply.

Take another, less artificial, example, put forward by the Australian philosopher John Jamieson Smart⁹. Consider the following statement: all of the amino acids involved in the composition of the proteins of all living beings are levogyres. This is an extremely robust empirical generalization for which, until recently, there were no known exceptions. However, there is no reason to think that the amino acids involved in the makeup of proteins of possible extra-terrestrial beings would necessarily be levogyres and not dextrogyres¹⁰. The fact that the amino acids making up the proteins present in known organisms on Earth are levogyres (L-amino acids) rather than dextrogyres (D-amino acids)¹¹ is probably the result of a historical contingency.

Returning to your specific question, Mendel’s first law, the law of segregation, refers to the independent disjunction of characteristics, and is applied to a single gene of which there are multiple versions (alleles). The law stipulates that each gamete can only carry one of these alleles¹². Mendel’s second law, the law of independent assortment, applies to multiple genes. It states that genes for different traits segregate independently of each other.

The term law, interpreted as a universal statement of unlimited scope, is problematic in both cases. Exceptions to the law of independent assortment were found very early in the study of genetics, in the years following 1900. These exceptions often resulted from the fact that the genes in question were present on the same chromosome, and did not, therefore, recombine at random as in cases where the chromosomes are independent. If the genes are close together on the chromosome, they rarely, if ever, recombine (through linkage). If they do recombine, this occurs through crossing over, rather than through chromosome mixing. Other exceptions occur due to epistasis, that is interactions between genes, meaning that the