If the relationships between Merleau-Ponty’s philosophy and the so-called “humanities” (a term that is clearly inadequate with respect to the historical situation in which Merleau-Ponty worked) is well known and widely studied, the same cannot be said with respect to the debate developed by Merleau-Ponty in connection to the natural sciences. This relative ignorance is largely due to the fact that, until recently, only a reduced number of texts were known which could afford an evaluation of Merleau-Ponty’s interests for the natural sciences and for the problem of the concept of nature as a whole. The publication of the three – decisive in­deed – lecture courses held by Merleau-Ponty at the Collège de France, and focusing on nature, deeply changed this picture. Obviously some aspects concerning the contents of these lectures were already known, in particular thanks to the publication of the “résumés de cours”, the summaries written by Merleau-Ponty himself at the end of each year. But these summaries, however relevant and instructive, could scarcely offer an exhaustive account of the richness and complexity of Merleau-Ponty’s own project. Thanks to the publication of the course notes we can now better evaluate the im­portance and the far-reaching range of the questions that the French philosopher was working on, and also better understand the meaning of the elusive expression that Merleau-Ponty chose for his project, that very “ontology of the flesh” which is often, still today, considered as a meta­phorical expression whose meaning remains unfathomable.
After twenty years of scholarship, the meaning of the investigation on nature for Merleau-Ponty’s phenomenological project is far from being exhausted. But some important pathmarks have been established. The rele­vance of this theme for his philosophy was stressed by Merleau-Ponty right at the start of his career, when setting up the task of his “Structure of behaviour” in terms of the study of the relationship between nature and consciousness. And yet only the publication of the lectures on nature permitted to really overcome the negligence with respect to this statement. Nature is indeed at the core of Merleau-Ponty’s phenomenology, yet this simple truth immediately raises complex questions. In the first place, the definition of the notion of nature with which Merleau-Ponty works is to be clarified. The reason of this choice seems rather clear: Merleau-Ponty after all is the philosopher of incarnated subjectivity. But this triviality conceals intricate entanglements. Merleau-Ponty is fully aware of the fact that an investigation of the natural bonds that attach subjectivity to natural life requires a doubling of investigation itself, for in this case the nature of the inquirer, the human subject, affects the nature of the inquired, and vice versa. Nature thus is not only an object of investigation, but also, and perhaps most of all, the “soil” of investigation itself, for it is the horizon and the “ground” from which a subject emerges. In other words, in this process of emergence, something “of” nature brings nature itself to its own truth.
From this perspective it becomes clear that the very distinction and splitting of the investigation on nature into a philosophical and a scientific side is not simply rejected, but rather intertwined by Merleau-Ponty in view of an overcoming of commonsensical platitudes. The very opposition of philosophers into the realist versus the idealist side, and the connected attempt at demonstrating that phenomenology should either be naturalized or on the contrary preserved in its spiritual purity, is surpassed in direction of a truly phenomenological understanding of manifestation, according to which both sides matter and must be conceptually understood, but what is usually overlooked, and phenomenology definitively on the contrary shows, is the relevance of their mutual interrelation, the third term which is actually the first one.
Nature thus is investigated by Merleau-Ponty both and simultaneously from a philosophical and a scientific perspective, thus factually negating their mutual exclusion while preserving their differences. His analyses of the developments of twenty-century physics are obviously carried on from the confessed standpoint of a philosopher who does not aim at replacing physicists themselves in a naïve attempt at teaching them the truth they were not able to see. Rather, Merleau-Ponty wants to show that twenty-century physics poses truly philosophical problems, which require an adequate philosophical answer. It is the naïve philosophy of the physicists to be outdated by their effective discoveries. Hence the need to retrieve, in a genealogical attitude, the classical philosophical roots that support this outdated philosophy. And the parallel unearthing of a possible different understanding of nature, which was somehow already present in many phi­losophical approaches, but which only the revolutions of the twentieth century forced scientists and philosophers alike to take really seriously. In the end, it is a different conception of truth that is emerging from the discoveries of physical science, as well as from other scientific realms, in particular those concerned with life. But the notion of truth, which is thus progressively uncovered, urges philosophy to react and to critically in­terrogate itself, trying to come to terms with the end of a tradition while not closing itself into sterile historiographical repetitions or indulging in the celebration of the end of thinking.
A full evaluation of Merleau-Ponty’s project is yet to be achieved. The essays included in this issue offer a wide range of approaches, varying from more philosophical discussions of Merleau-Ponty’s key concepts to detailed analyses of some of the most relevant proposals contained in Merleau-Ponty’s works (mostly, but not only, the lectures at the Collège de France). The confrontation between Merleau-Ponty’s philosophy of nature and of the natural sciences, with their epistemological questions, is an open chapter of investigation, which hopefully might lead to further findings and results.

Contents
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Luca Vanzago, Introduction
Ted Toadvine, Tempo naturale e natura immemoriale
Luca Vanzago, The Problem of Nature between Philosophy and Science. Merleau-Ponty’s Phenomenological Ontology and its Epistemological Implica­tions
Roberta Lanfredini, Essenza e Natura: Husserl e Merleau-Ponty sulla fondazione dell’esse­re vivente
Christopher Pollard, Merleau-Ponty and Embodied Cognitive Science
Gianluca De Fazio, L’Essere pre-logico. Una lettura ontologica dell’interpretazione di Co­penhagen a partire da Merleau-Ponty
Danilo Manca, La scienza allo stato nascente. Merleau-Ponty e Sellars sull’immagine scientifica della natura
Darian Meacham, Sense and Life: Merleau-Ponty’s Philosophy of Nature and Evolutio­nary Biology
Franck Robert, Merleau-Ponty, Whitehead, une pensée de la vie
Claus Halberg, Emergent Life: Addressing the “Ontological-Diplopia” of the 21st Century with Merleau-Ponty and Deacon
Prisca Amoroso, Prospettive ecologiche nell’opera di Merleau-Ponty