1 Never, it seems, has the old question of “Man’s place in nature” been so topical. But never has the answer seemed more obscure. That is because such a question is caught up today in a contradictory injunction or double bind, according to which humanity would be a species both equal and superior to other species. On the one hand, an anti-anthropocentric injunction wants humanity to renounce the privilege it has granted itself within nature, on the grounds that it is in reality only one species among others, equal to others. This injunction, which seeks to break with anthropocentrism, is the combined result of a series of transformations that have affected many contemporary forms of knowledge: developments in evolutionary biology since Darwin, which place the human species within a natural history that includes and exceeds it; the advances of paleoanthropology in understanding the process of hominization, which integrate the different species of hominins that existed before or at the same time as the only current human species, the only one to survive, Homo sapiens; the revolution of comparative ethology, which blurred the boundary between animals and humans and which led to a reflection on the animal origins of culture; the anti-humanist vogue in post-war French philosophy, which promoted the theme of the death of Man; environmental ethics, which challenge moral anthropocentrism and substitute it with an ethics that is sometimes pathocentric, sometimes biocentric, sometimes ecocentric; the ontological turn in anthropology, which has demonstrated that the Man-nature dualism is a socio-historical construction specific to the modern West and which enjoins us to compare it with other ontologies or other ways of composing worlds; etc. It seems to be a given that this vast body of knowledge contributes today to making anthropocentrism a definitively obsolete category. And it is not the least irony of history that anthropocentric societies are now considered a form of archaism, or at least a stage in history destined to be overcome, whereas societies long qualified as archaic seem to become in return the future of our societies once they have been washed of their anthropocentrism (but perhaps not of their evolutionism, whose meaning has perhaps only been reversed...) [1]

2 Alongside this anti-anthropocentric injunction, we also observe in contemporary thought a contrary injunction, which could be described as neo-anthropocentric. An anthropocentric injunction, to be sure, since it invokes the uniqueness, the singularity or the exceptionality of humanity within nature; but it is a neo-anthropocentric injunction, insofar as it invokes it in the name of a relatively new fact: that humanity is today the only species that has the power to threaten its conditions of existence on the scale of the biosphere, while at the same time becoming aware of this power and criticizing it. Here again, this injunction is based on a series of contemporary reflections whose importance cannot be underestimated, especially since they often come from the same fields of knowledge as the previous ones: reflections on human evolution since the Neolithic, as a species that is phylogenetically increasingly unsuited to the conditions of existence that it has itself contributed to create; work in neurobiology, which underlines the singularity of the neotenic human brain, whose evolution and development are based on its extraordinarily plastic character compared to the other cerebral systems, even those of the large non-human primates; the various ethological questions about the weight that the life of humans as omnivorous hunters could have had on the intensity of their behaviors of cooperation and mutual aid as well as predation and destruction; the philosophies of nature and life that demonstrate the singularity of the psychic and collective individuation of humans compared to the physico-chemical and biological individuations; environmental ethics which insist on the anthropogenic character of all ethics, underlining that Man is the only source of values, if not its only place; the post-war philosophies elaborated in the face of fear of nuclear war and ecological catastrophe, endowing humanity with a unique responsibility within nature; the reflections, stemming from environmental history and Earth system science, on the Anthropocene, or the Capitalocene, or their different avatars, according to which the human species has become socialized in such a way that it now constitutes a telluric force unprecedented in the history of the Earth, inaugurating a mutation of biogeochemical cycles and a new geological age; etc. And here again, it is not the least of the ironies of history to note that some ecologists, when they call for an urgent reaction to the current catastrophe, invoke “the hummingbird’s share” [la part du colibri], or some model of instinctive or intelligent animal behavior, to designate this reaction that no one expects from hummingbirds or even from the most intelligent of animals, but only from human beings...

3 If these two injunctions seem contradictory, it is because, in the same gesture, they abolish and reinforce the privileges of humanity within nature. Humanity is simultaneously decentered and recentered, so that we no longer know which center to devote ourselves to. Anthropocentrism has become the core of an antinomy of contemporary reason. This contradictory injunction manifests the need to find a way out of the sterile confrontation between anthropocentrism and zoologism, one claiming to extract humanity from the natural world to consider it as a separate entity, even as a summit of evolution, the other claiming that humanity is an animal species like the others, even inferior because it is capable of the greatest stupidity and the worst atrocities. Clément Rosset satirized this vain opposition and the moralizing speeches that it continues to convey, more than fifty years ago, in his all-too-forgotten Lettre sur les chimpanzés. And if the post-war period was haunted by the question of Man, it was first of all a crisis of humanism, that is to say, at bottom, of the relationship between Man and culture. It is only more recently that the confrontation has shifted from the question of humanism to that of anthropocentrism, that is to say, of the place of Man in nature. Testifying to this displacement, and also to the possibility of staying in the interval between the two questions, is, for example, the protean and transversal work of Fernand Deligny, who led, in contact with autistic children and the most diverse intellectual productions, a tireless attempt to explore this “breach” which at the same time separates and connects biological nature and symbolic culture, this difference that is both unmistakable and unlocalizable between “the human-by-nature” and the “human-that-we-are”. The fact remains that, from now on, the fight has changed spirit. Thanks to the rise of a cross-disciplinary ecological thought, thanks to a growing and generalized awareness not only of the inscription of humanity in nature but also of their real entanglement, the “battlefield” has shifted. Just as the history of human societies is now included in environmental history, the demand for a critique of humanist reason is now taken up, displaced, and encompassed in the need for a critique of anthropocentric reason.

4 Faced with such a problem, the contributions that make up this issue were therefore invited to place themselves in the line of those philosophies of life or nature which, by combining the respective contributions of contemporary natural sciences and philosophy, have sought to determine under what conditions it is possible to reinscribe humanity fully within an enlarged nature, without dissolving its specificity. In other words, how can we put back to back anthropocentric dualism, which opposes Man and nature, and reductionist monism, which dissolves the former into the latter? It has been said, for example, about Ruyer’s conception of man that he intended both to “show to what extent Man is a living being like any other [...] and to determine what makes the irreducible human singularity”. [2] To what extent can philosophy mobilize a perspective of this kind to trace a way out of the contemporary antinomy of anthropocentrism? In its studies of the origins of humanity, what criterion can paleoanthropology invoke, for example, to think about the specificity of humans (see Mathilde Lequin’s article)? What place should be reserved for the development and evolution of the human brain (see André Conrad’s article on Ruyer and the interview with Alain Prochiantz and Jean-Jacques Hublin)? At the other end of history, faced with the possibility of an apocalyptic end of humanity, how can philosophy contribute to build another conception of human nature and of its social and technical inventiveness (see Cécile Malaspina’s article on Simondon)? Can we imagine, for example, that the animal is the future of Man (see the zoofuturist proposals of Dominique Lestel)? And between the question of the origin and that of the end, what are the theoretical and practical implications of the inclusion of human history within natural history (see the article by Alexis Boisseau and Mathilde Tahar on Bergson and Ruyer)? Moreover, isn’t the central importance of a reflection on history – whether human or natural – the sign that humans have an incomparable experience of the possibilities that never cease to haunt history, and thus to haunt themselves (see Didier Debaise’s article on Whitehead)?

5 If this issue brings together philosophical contributions that dialogue with the natural and life sciences, it is naturally because these sciences have played a decisive role in the construction of this contradictory injunction or double bind. Historically, in fact, it became a constitutive paradox when the mechanism of natural selection, described by Darwin in 1859 in The Origin of Species, was applied to the emergence and evolution of human lineage in Thomas Huxley’s Man’s Place in Nature in 1863, and then in Darwin’s The Descent of Man in 1871. Since then, the fate of the theory of evolution, physical anthropology, paleoanthropology, developmental and evolutionary biology, seems inextricably linked to the question of how to simultaneously conceive the continuity and bifurcations of human evolution. On the one hand, the continuity of evolution inscribes humanity, even in its most noble intellectual and cultural achievements, in an entirely natural universal history, which can be traced back to the origins of life, and even of the universe. On the other hand, the more or less rapid and more or less recent bifurcations of the same evolution have given birth to this strange species of primate now haunted by the question of its emergence, its uniqueness and its end. Isn’t looking for the bifurcation within a continuous evolution comparable to the problem in mathematics of locating points of inflection on a curve? As for the emergence of the human lineage, it seems that we can multiply the singular points as much as we like: the manufacture of the first carved stone tools, bipedalism, encephalization, the domestication of fire, the exit from Africa, the cognitive or symbolic revolution, the disappearance of hominins other than Homo sapiens, the Neolithic revolution, the invention of writing, the scientific revolution, the two industrial revolutions, the nuclear age, the externalization of memory and intelligence in digital technologies, etc. – all these bifurcations do not break in any way the continuity of the evolutionary curve.

6 However, this unilinear conception of evolution is doubly insufficient. First, because we know that evolution cannot be represented in the form of a single curve. As Darwin showed, and as Bergson in turn will emphasize, evolution implies, on the contrary, the creation of divergent paths or lineages, which follow differentiated rhythms. Evolution is a tree, and even a bush. And we should not forget that, in the course of evolution, many branches have stopped their growth, that countless species have become extinct. The genus Homo is a good example of this, since Homo sapiens has become, since the disappearance of Denisova man and Neanderthal man, the last representative of its lineage, a species orphaned by its congeners. Moreover, this arborescent or bushy conception of evolution reveals itself to be insufficient as soon as we integrate all the phenomena of co-evolution, all the interdependencies between divergent evolutionary lineages. Finally, numerous contemporary studies constantly emphasize the extent to which the evolution of the human species cannot be separated from biogeochemical and socio-technical factors, which intervene in a decisive manner at different scales of time and space. Examples of such an entanglement between biology and culture are not lacking: climate variations in the Pleistocene and its stabilization in the Holocene, which led to the disappearance of the reindeer civilization and the emergence of a civilization that will take geology into another age (Anthropocene, Capitalocene); the importance to us of other organisms within us, such as our gut microbiota; the zoonotic epidemics that have plagued us from the Neolithic to the present day, of which the COVID-19 pandemic is the most recent example; the biological and cultural importance of sugar cultivation and consumption since the beginning of the colonization of the extra-Western world in modern times; the role of synthetic chemistry in the dissemination of endocrine disruptors that threaten pollinating insects, whose progressive disappearance in turn threatens agriculture and human nutrition... In short, if evolution is bushy, it is a bush whose many so-called divergent branches constantly come into contact, in complex co-evolutionary relationships, which imply reticular rather than arborescent or bushy models, and which suppose breaking with all forms of evolutionism – even with the idea of an ordered succession between matter, life, and mind. As Deleuze and Guattari point out, “the apparent order can be reversed, with cultural or technical phenomena providing a fertile soil, a good soup for the development of insects, bacteria, germs or even particles”. [3]

7 Consequently, it is obvious that we can no longer innocently maintain the idea of Man’s place in nature and the schema of genus and specific difference, which have served as a model for thinking about anthropological difference. Certainly, from Aristotle to Huxley, the arborescent schema of differentiation had changed in meaning: at the turn of the eighteenth century, the fixist order of things in space gave way to their historical evolution over time – opening up a new épistémè, the “age of history”, [4] affecting the human sciences as well as the natural sciences. Moreover, doesn’t the meaning that Huxley gives to the notion of “place” in the second half of the nineteenth century testify to this new paradigm common to the human and natural sciences? This notion seems to mark the deep affinity between the study of the biological mechanisms of species evolution, in which man would occupy the summit, and the interest in the sociological mechanisms of social differentiation, that is to say, in the statuses and rights that are supposed to derive from an advantageous position or an eminent rank within a hierarchical set, but where an eminent place in the hierarchy can no longer claim any natural privilege linked to origin, as was the case in the fixist Ancien Régime of things, because it must now be presented as the immanent product of a historical evolution. But how to pose the problem adequately, once we have said that an adequate understanding of evolution leads us to renounce all evolutionism? We probably have to abandon the idea of “place in nature” in favor of the idea of Man as “part of nature”, following an inspiration found in Spinoza’s Ethics (pars naturae) as well as in Marx’s Manuscripts of 1844 (Teil der Natur). From this point of view, any singular individual, and thus also the human, has no other essence than relational (and not substantial) and must be “conceived both in relation to the parts that compose it and in relation to a larger whole of which it is itself a part”. [5]

8 Therefore, within this relational ontology, what is it that singularizes the relationships that the human parts of nature establish with other parts of nature? What is the singularity of their regime of individuation? As the contributions to this issue suggest, this singularity may have two complementary aspects. On the one hand, humans would have the capacity to establish complex relationships with a multiplicity of other entities, human and non-human, inside and outside of them, which constitute potentialities of individuation (extensive aspect) for them. On the other hand, humans would never better accomplish their “nature” or their “essence”, i.e. would never better fulfill their potentialities, than by experiencing individuating relations that widen the meaning of human experience (intensive aspect). From this point of view, the schema of genus and the specific difference would then fade away behind the idea that a human individual carries out their “singular essence” only insofar as their individuation does not objectively distinguish itself any more from their “generic essence”. “Not man as the king of creation, but rather the being who is in intimate contact with the profound life of all forms or all types of beings, who is responsible for even the stars and animal life”. [6] Isn’t there a criterion here that would allow philosophy to evaluate the content of these relations, and thus to give a philosophical meaning to the categories of “success” and “failure” that the scientific theory of evolution has never ceased to use – success no longer being measured by adaptation, survival, and reproduction, that is to say, by the future of the species in history, but by the multiplicity and intensity of its individuating relationships, that is to say, by its collective becomings?