Schopenhauer’s metaphysics of nature is paradoxically positioned both in opposition to and in dialogue with Naturphilosophie, as developed in Schelling’s thought. This presentation will examine how Schopenhauer gradually distanced himself from this intellectual heritage, especially as contemporary scientific advancements – particularly in physiology – shaped his evolving ideas. By considering the role of figures such as Blumenbach, Kielmeyer and Goethe, it highlights how empirical research provided Schopenhauer with conceptual tools that allowed him to rethink the relation between science and metaphysics.

Palavras-chave: Life sciences (19th century); Metaphysics of experience; Naturphilosophie; Philosophy of science; Schelling

A metafísica da natureza de Schopenhauer situa-se, paradoxalmente, tanto em oposição quanto em diálogo com a Naturphilosophie, tal como desenvolvida no pensamento de Schelling. Esta apresentação examinará como Schopenhauer se distanciou gradualmente dessa herança intelectual, especialmente à medida que os avanços científicos da época – particularmente na fisiologia – moldaram a evolução de suas ideias. Ao considerar o papel de figuras como Blumenbach, Kielmeyer e Goethe, destaca-se como a pesquisa empírica forneceu a Schopenhauer ferramentas conceituais que lhe permitiram repensar a relação entre ciência e metafísica.

Keywords: Ciências da vida (século XIX); Metafísica da experiência; Naturphilosophie; Filosofia da ciência; Schelling

If the importance of a thinker can be measured by his impact on the history of philosophy, then that of Schopenhauer is beyond doubt. From Nietzsche to Freud, and through philosophical anthropology (Gehlen, Plessner, etc.), Schopenhauer's influence is both profound and undeniable. In the literary field, he is one of the philosophers who has had the most lasting influence on literary creation^¹. If we then turn upstream to consider Schopenhauer’s relation to his predecessors, this too opens up a rich and complex field, of which this symposium already gives us a good overview. Paul Deussen does not hesitate to assert in The Elements of Metaphysics (1877) that “through numerous and remarkable analogies, he [Schopenhauer] is to Kant what Plato is to Socrates” (DEUSSEN, 1899, p. 67), thus underlining, perhaps with the emphasis of a disciple, the richness of such a lineage. The very first critical reception of The World as Will and Representation already emphasised the fact that Schopenhauer seemed to be at the crossroads between Kant^², Schelling and Böhme^³. And now, for historians of philosophy, Schopenhauer appears as a node that allows us to think about the extension of a philosophy entirely renewed by the Kantian position. If this central role was not immediately apparent, it was mainly because, in the philosophical debates of his time, Schopenhauer seemed, at the time of the publication of the first two editions of his magnum opus, The World as Will and Representation (1819/1844), to have been relegated to a kind of marginality that made him little visible to his contemporaries. However, this should not obscure the way in which Schopenhauer was able, in part, to shape his own theory through contact with authors he rejected, notably the importance of Naturphilosophie and, more generally, the thought of Schelling. Schopenhauer's growing success from 1853 onwards attests to the fact that he did indeed offer a new way of thinking. And indeed, if we look beyond the pessimistic dimension that seems perfectly in tune with the spirit of the times, we cannot deny the impact that his new vision of man had, particularly on artists and writers. By placing his notion of will at the heart of nature – and therefore of man – he removed the primacy of rationality in favour of a blind impulse, effectively shattering the classic and advantageous representation that man had been able to have of himself until then. Such a rupture can only be decisive if it is based on a vast body of empirical material provided largely by the natural sciences, which at that time were undergoing decisive transformations. For this reason, we would like to examine more closely the initial dialogue that Schopenhauer established with the empirical sciences of his time and their philosophical translation into naturphilosophie. His fascination/repulsion with the latter is all the more interesting in that it reflects, in a way, a movement specific to a period that saw the positive sciences gradually emancipate themselves from philosophical tutelage. Schopenhauer's thinking thus acts as a kind of reaction to this process of scientific autonomy, in that it asserts the need to rethink the link that hitherto existed between science and philosophy. Schopenhauer drew on the latest scientific and empirical knowledge to challenge the classical model of natural philosophy and sought to lay new foundations by proposing a metaphysics of nature that would ultimately present itself as a “science of experience”^⁴.

Thus, after recalling Schopenhauer's primary interest in science, emphasising in particular that it is both theoretical and practical, we will examine in more detail the critical discussion he engages with Naturphilosophie and Schelling's thought, showing that he finds there a kind of milieu in which his thought can emerge and assert itself, differentiating itself to such an extent that we can say that his metaphysics of nature seems to be developed “against” this current in the very literal sense that it relies “on” it in order to develop.

Schopenhauer's dialogue with German philosophy is, in a sense, delayed or mediated, initially, by his scientific work. While it is common for philosophers to take an interest in the sciences of their time, Schopenhauer was one of those for whom this interest manifested itself on both a theoretical and practical level. His biography provides ample information on this point. The curriculum vitae (GBr, [55]) he sent to the University of Berlin recalls an anecdote that reveals his early interest in science: in 1805, when he was only 17 years old and still an apprentice at the Hamburg trading house, he did not hesitate to lie in order to take time off and attend a series of lectures on phrenology given by Franz Joseph Gall (1758–1828). Far from being anecdotal, this interest in science came to fruition in 1806 when, freed from the promise he had made to his father to run the family business, he resumed his classical studies and, in 1809, at the age of 21, reached a level sufficient to enrol at university. His choice of Göttingen rather than Jena – even though Jena was closer to Weimar, where he was residing – was another strong indication of his decision to pursue a career in science. Göttingen was, in fact, an independent scientific centre that could rival Paris or London without blushing, but which, from a philosophical point of view, seemed more backward when compared to the University of Jena, where Fichte, Schelling and Hegel had succeeded one another around 1800. In reality, it was not until the summer of 1810, with the arrival of Schulze, the famous author of Enésidème, that the young Schopenhauer began to turn towards philosophy. Nevertheless, whether in Göttingen or Berlin, Schopenhauer ended up acquiring a solid scientific education, for even when he committed himself completely to philosophy, he did not abandon the sciences to such an extent that, if we take into account his four years of university studies, it becomes evident that he attended more science courses than philosophy courses.

It is clear that this early relationship with sciences informed his approach to philosophy and the development of his thinking. This is all the more true given that this relationship was not only theoretical but also, as we have already pointed out, had a very practical dimension. For a detailed description of this engagement and its particularities, it is useful to refer to Marco Segala’s latest book: A Convex Mirror (SEGALA, 2024). Within the limits of our presentation, we will focus on just two figures to illustrate this dual relationship with the natural sciences: Blumenbach and Goethe, leaving the question of Kielmeyer’s influence for the following paragraph.

Since the work of Timothy Lenoir (1948) and the critiques of John Zammito (2018) and Andrea Gambarotto (2018), it has become easier to understand the decisive importance of Johann Friedrich Blumenbach (1752–1840) in the development of the natural sciences in general and for Schopenhauer in particular. In The Strategy of Life, Lenoir recalls a simple fact:

At least half of the major contributors to German biological science during the early nineteenth century were his students or at least claimed to have been inspired by the man. Among his most notable students were Alexander von Humboldt, Carl Friedrich Kielmeyer, Georg Reinhold Treviranus, Heinrich Friedrich Link, Johann Friedrich Meckel, Johannes Illiger, Rudolph Wagner and many others^⁵.

It is therefore not impossible that Schopenhauer's choice of Göttingen over Jena was motivated by the presence of Blumenbach, who had succeeded the equally famous Albrecht von Haller (1708–1777). Both men embodied the rise of physiology as an independent science, rethinking it as a "moving anatomy" capable of integrating the achievements of the experimental sciences, particularly physics and chemistry. By publishing Institutiones Physiologicae in 1787, Blumenbach perpetuated his physiological theories by producing the reference manual for the brand-new science of physiology.

Blumenbach's influence was decisive in the young philosopher's education, as his teaching was constantly open to philosophical questions. Blumenbach developed many concepts that would have a direct impact on the development of The World. The notion of the formative impulse [Bildungstrieb or nisus formativus], for example, would prove to be fruitful. At the time of its introduction, it had already sparked a dialogue with leading philosophers such as Kant and Schelling. From Haller to Blumenbach, and then on to Kielmeyer and Treviranus, a whole conception of vital force took shape that would profoundly influence Schopenhauer's understanding of organic life and establish itself as the first “concrete” model of the action of the will. Here he discovered concepts that were not the result of vague abstractions and which, in his view, already offered an alternative to what natural philosophy was attempting to achieve. It was in fact experimental investigations^⁶ that led Blumenbach to formulate the hypothesis of such a formative impulse. Neither mechanical nor reducible to animistic vitalism, the “formative impulse”, which he posits hypothetically, is a vital force (like the irritability that Haller had already highlighted) whose cause is unknown and which does not need to be pursued in order to better understand living beings. In section 45 of his Physiological Institutions, he explains this point in a paragraph that is central to understanding the genesis of Schopenhauer's concept of will:

Since then, I have become more and more convinced every day that there is a particular force in all organic bodies that is as ancient and as enduring as they are, by virtue of which they take on the form that suits them through generation, preserve it through nutrition, and, if it is altered, repair it as much as possible through reproduction. To distinguish it from other vital forces, I have called it the force of formation. I have thus designated in an abstract manner, not the cause of the phenomena I wanted to describe, but the sustained effect of their duration and universality. We use the terms attraction or gravitation in much the same way to express forces whose causes are still buried in the deepest darkness^⁷.

The comparison with Newtonian gravity is a masterstroke. Blumenbach thus validates his concept by showing that what gives it meaning is precisely all the work of observing the effects of such a force within organisms. He may not be able to offer a priori proof of its essence, but he observes its effectiveness every day in the most important phenomena of life (generation, nutrition, reproduction). Kant himself, in paragraph 81 of his Critique of Judgment, does not hesitate to praise Blumenbach's foresight. But for Blumenbach, it is not a regulatory principle but a constitutive principle that acts as a causal force in the development of organic bodies. It is easy to guess what Schopenhauer took from Blumenbach's theory of this particular life force that pushes life towards specific forms, maintains it within individuals and can even partially restore it^⁸ .

By studying physiology closely, Schopenhauer witnessed a constant dialogue between the natural sciences and philosophy. For him, this new science—what he regarded as “the summit of all natural science” (GBr, [284]) —imposed the necessity of linking the results of empirical inquiry with the materials upon which metaphysics must reflect. The x to which this formative impulse refers thus constitutes a form of openness for a coherent metaphysical thought that seeks to consider experience in its entirety in order to produce a complete theory.

We must now turn to the practical dimension of Schopenhauer’s interest in the natural sciences – an interest that took concrete form in particular through his collaboration with the famous Goethe (1749-1832) in 1813-1814^⁹ . As this episode is better known, we can move on more quickly from the details to better put into perspective the fact that it is decisive in understanding Schopenhauer's conception of true knowledge and, in particular, the role that experience plays in its development. It is important not to underestimate the significance of such an encounter, and when examining Schopenhauer's relationship with German philosophy, it seems entirely legitimate to devote a discussion to the famous poet who, in Schopenhauer's eyes, embodied both a role model and, in many respects, a surrogate father figure. This research provided our young philosopher with an opportunity to devote himself to a genuine scientific essay on sight and colours, the specificity of which lay precisely in the physiological roots he gave to this problem – an approach that would appear not as a form of complacency towards his mentor, but rather as a confirmation of his research skills, while consolidating the main thrust of his own doctrine by giving a physiological embodiment to the central idea of the world as representation.

The Farbenlehre is, in the scientific field, Goethe's great achievement, as Schopenhauer points out in a letter to the English translator of the work, C. L. Eastlake, in which he reminds him that this work "occupied, much more than poetry, the thoughts of its author throughout his life" (GBr, [175]). In reality, behind the object studied, Goethe also sought to defend an entire conception of science against the progress of Newtonian optics, which completed a mechanistic view of the world by providing a geometric optics capable of ensuring the total rationalisation of the perceived world. This mistrust of analysis and the reduction of reality to equations of mechanical physics would also be at the heart of the conception of science that Schopenhauer would later develop in Book I of The World, and whose study of the manuscripts shows us that the main arguments had been put forward in 1814, that is, at the very moment when Schopenhauer was working with Goethe to develop this new theory of light and colour.

The final draft of the treatise in 1816 demonstrates the extent to which Schopenhauer was able to assert his own theory by developing the purely physiological part of Goethe's theory. Schopenhauer took up only part of the analyses in the Farbenlehre and developed the passage in which Goethe asserts that certain colours (called physiological colours) originate in the physiology of the eye itself, in order to generalise this discovery to the entire colour wheel – each colour then corresponding to a certain activity of the retina^¹⁰ (white referring to maximum activity and black to complete inactivity). This break with his mentor allowed Schopenhauer to refine the specificity of his thinking and to give further substance to ideas already set out in his dissertation On the Fourfold Root of the Principle of Sufficient Reason (1813) by confirming some of his epistemological hypotheses. In reality, unlike Goethe, Schopenhauer was more interested in sight than in colours. The first chapter of the essay, entitled “On Vision”, can be read as a precise demonstration of the assertion that “all intuition is intellectual”, and thus be seen as an opportunity to develop once again, after §19 of On the Fourfold Root, the singular role that understanding plays in his philosophy. This understanding of vision shows how, based on the multiple affections of the retina, the understanding immediately reconstructs our representation of the outside world. The straightening of the retinal image or the correction of binocular vision are good examples of this. But what will become central to this analysis is the anatomical inscription of this process of synthesis. The essay On Vision and Colours allows us to take a step back in the process of conceptualisation and shed light on the entire physiological basis of representation by explaining the central role of excitation. The value of this essay should not be underestimated, for it is by exploring the specific example of vision that Schopenhauer most openly reveals the physiological aspect of his theory, which would become central to his writing of The World.

Thus, his encounter with Goethe was decisive, even though they differed on many points: Goethe developed a refined form of empiricism by focusing on nature and its objects, while Schopenhauer remained firmly anchored in the subject, defending a transcendental approach inherited from Kant. Nevertheless, Goethe's morphological approach and concepts such as that of the “original phenomenon”^¹¹ (Urphänomen) would influence Schopenhauer's thinking at the moment when the essential ideas of his metaphysics crystallised. It is even highly probable that the central idea of developing a metaphysics understood as a metaphysics of experience owes much to his acquaintance with Goethe and his works. It was through Goethe that he acquired a conception of the world as a totality that no longer had anything in common with the totality of idealistic reason. This new relation to experience explains the decisive weight that the sciences bore in the emergence of his system.

The names of Blumenbach and Goethe are often mentioned as prestigious figures adorning Schopenhauer’s biography. Yet the direct and living relationship they maintained with what must at first be considered their disciple or student had a profound impact on the elaboration of the metaphysics of The World as Will and Representation. Their impact was not limited to doctrinal exchange but was much more closely linked to the way they practised and conceived of science, making it an essential starting point for any serious philosophical reflection. It is from this point of view that they ultimately became models for Schopenhauer, enabling him to adopt a critical stance on many philosophical works that sought to reveal the secrets of nature. Nevertheless, if we want to gain a clear understanding of Schopenhauer's metaphysics of nature, it is essential not to dismiss Naturphilosophie too quickly on the basis of what he says about it in his published work. This often had the effect of fertilising Schopenhauer's thinking by forcing him to better define the framework of what would become his own metaphysics of nature; above all, his criticisms of it too often tend to obscure the fact that this theory made it possible to establish a framework and promote the development of the natural sciences, often taking a similar starting point to his own.

We have already mentioned that Schopenhauer was a contemporary of a decisive and, in many respects, definitive break between science and philosophy. Nevertheless, at the time he wrote the first version of The World, metaphysics continued to provide a frame of reference for various scientific investigations by postulating a unity of nature and offering a coherent conceptual horizon. Thus, he was able to see for himself how Blumenbach's research was in dialogue with Goethe, Kant and Schelling. The latter was a decisive reference at the time, as he promised to do in the field of natural sciences what Kant, with his Metaphysical Foundations of Natural Science (1786), had succeeded in doing for the physical sciences, namely to lay the foundations for future research. Kant, in fact, had not allowed his own research programme to be extended beyond physics; he even seemed to consider the natural sciences as belonging more to the realm of art than to that of science, as the preface to Metaphysical Foundations bluntly reminds us, emphasising the lack of necessity of the principles of chemistry, which seem to have been obtained by experiment rather than by strict deduction^¹² . Schelling, on the contrary, in his First Outline of a System of Philosophy of Nature (1799), succeeded in demonstrating, in Schopenhauer's view, that nature should be an object of philosophical research and that the philosophy of nature was necessary to define and establish nature as an object of scientific research. Reading the Nachlass quickly brings us face to face with the idea that the project of philosophy of nature that Schopenhauer undertook in World as Will and Representation is largely based on an in-depth discussion of Kant and Schelling, or rather Schelling versus Kant. Schopenhauer borrows important concepts from Naturphilosophie: polarity, certain aspects of analogy, but, above all the notion of Stufenfolge (graduated series, or gradation of natural forms). In a remarkable fragment from 1817, which constitutes the theoretical horizon within which he intends to develop his own metaphysics, Schopenhauer nevertheless recognises Schelling as a precursor – I quote: “in his effort to demonstrate the analogy between all phenomena of nature”^¹³. I already had the opportunity to examine this question of analogy at the 9th colloquium so this time I will choose that of Stufenfolge to illustrate this convergence.

Stufenfolge is, in fact, emblematic of Schopenhauer’s conflicted relation to Schelling. Its importance to the system is considerable. To be convinced of this, we need only recall that in the first edition of The World, Schopenhauer depicts the phenomenal world as an objectification of the will in an indefinite series of gradations (Abstufungen) of inorganic forces up to the man of genius. But very quickly the connection with Schelling disappeared and his name even came to be associated little by little with a form of betrayal. Schopenhauer, who had become familiar with this notion by reading Schelling, ended up accusing him of plagiarism, pointing to the original source of this concept in the decisive speech given by Kielmeyer at the Military Academy in Stuttgart in 1793 (KIELMEYER, 1993). In his view, this speech constituted nothing less than the research programme that enabled the emergence of a true science of nature and, more specifically, the birth of biology. At the heart of this text, Kielmeyer proposed a temporalisation of the great chain of being, thus laying the foundations for the Stufenfolge. It is undeniable that a few years before Schelling's first texts on the subject, Kielmeyer was already describing life and organisation as successive stages of chemical interactions in a process in which inorganic forces created increasingly complex interconnections, thus causing the emergence of specific forces – organic forces – governed by precise biological laws.

Schopenhauer came into contact with Kielmeyer's ideas through Horkel's lectures in Berlin and subsequently purchased the 1814 reprint of Kielmeyer's discourse. Thus, contrary to what he suggests, it was indeed through reading Schelling that he developed this concept and transposed it into his own metaphysics of nature. Here again, it is important not to place too much trust in Schopenhauer's own account of the formation of his system. Marco Segala highlights the credulity of many biographers who take at face value the story that Schopenhauer blindly followed Schulze's advice. Indeed, in a letter to Professor Erdmann, who asked him for some biographical details in April 1851, Schopenhauer states:

I would like to point out that I entered the University of Göttingen in 1809, where I attended courses in natural sciences and history, before being awakened to philosophy during the second semester by the lectures of G. E. Schulze, Enésidème. He wisely advised me to devote my personal efforts first exclusively to Plato and Kant, and not to look at others, notably Aristotle or Spinoza, until I had finished with them. Following this advice, I found myself very well^¹⁴.

Precisely because he began his education with the sciences, and particularly medicine and physiology, Schopenhauer was immediately brought into contact with Schelling's writings. It is therefore not surprising that the record of his borrowings from the university library in the summer of 1810 tells a very different story: the first philosophy book he borrowed, even before consulting a dialogue by Plato, was Schelling's On the World Soul, followed by his Ideas for a Philosophy of Nature, and it was not until October that he began reading Kant, particularly the Metaphysical Foundations of Natural Science. Schelling thus enabled him to familiarise himself with Kielmeyer's ideas, but he was also the one who proposed an immediate translation of them on the metaphysical level, integrating them directly into a new conception of ontology. It is precisely in On the World Soul that Schelling most clearly sets out these developments, rethinking the Stufenfolge on the basis of the concept of power (Potenz). Schelling then proposes a model for explaining nature that is capable of articulating a unity of the absolute and a multiplicity through a dynamic differentiation^¹⁵ , which provides a framework similar to that which Schopenhauer would later seek to establish in his metaphysics of nature, which he complexified by introducing, with the Ideas, different levels of objectification – while at the same time eliminating any genuine teleological perspective, even if representation seems saturated with it^¹⁶ . We can then understand that teleology as we perceive it in nature is only an objectification/transposition within time of the will, which as a thing in itself lies completely outside it. The complexity of its being manifests itself in nature for us in a progressive form embodied by the ascending series of Ideas, whose Stufenfolge is the correct translation^¹⁷ .

In reality, once we put aside the mockery and witticisms, we realise that Schopenhauer accords Schelling genuine expertise in the sciences. But this expertise did not lead Schelling to reconsider their epistemic status. For Schopenhauer, by contrast, it now became evident that scientific inquiry no longer required a prior philosophical deduction of the concept of nature or of its principles. The sciences are based on the principle of sufficient reason and nothing else. The relationship between science and philosophy needs to be rethought – and this is precisely what he intends to do by proposing a “philosophy of science”. Thus, with hindsight, it is clear that Schelling stands out as a reference for Schopenhauer, not so much for the answers he provides as for the questions and problems he raises. What seems interesting to highlight here is the way in which Schopenhauer turns the scientific reference to Kielmeyer on its head in order to definitively undermine the model established by Schelling and Naturphilosophie.

A careful reading of Schopenhauer's criticisms of Schelling's system shows that, beyond a profound metaphysical disagreement on the question of the thing-in-itself, it is above all the status of the link between science and philosophy that is called into question. The Nachlass lists the points of tension that prevent Schopenhauer from rallying to Schelling's Naturphilosophie: there is a clear rejection of his theory of powers and, more generally, of the dynamism that runs through the system – a rejection motivated by the contradiction that Schopenhauer detects behind the notion of force^¹⁸. The latter, drawn from the physical world, cannot, in fact, hope to shed any light on the metaphysics of nature. But behind this, the real problem remains the epistemic status

of the philosophy of nature itself. In order not to repeat the errors of Naturphilosophie, it is therefore necessary to clearly delimit the domains of science and philosophy. Schopenhauer concludes a fragment from 1814 on Naturphilosophie with a scathing remark:

All philosophers have gone astray by considering philosophy as a science and trying to find it in the continuity of the principle of sufficient reason. Naturphilosophie is the error of supposing that the ideal attained by physics would be philosophy^¹⁹. (HN I, [328], p. 206).

Schopenhauer does not seek to disparage scientific knowledge, but rather to show that science and philosophy provide two different types of conceptual knowledge. It is therefore not necessary to demand that philosophy deduce the concept of nature or its principles. The sciences are based on the principle of reason and only on that principle. In short, philosophy seeks to understand what the world is and therefore establishes that the world is will, while science focuses on why and explains the sequence of phenomena within a world that is precisely this objectified will. Schopenhauer thus acknowledges the autonomy of the sciences, a fact that does not prevent their results from being relevant to philosophy, quite the contrary. The analysis of this content will become the subject of a new philosophical discipline – the philosophy of science – devoted entirely to the analysis of possible interactions with philosophical knowledge. Its role will be no less important within a philosophy that rethinks metaphysics as a metaphysics of experience.

In the Nachlass, Schopenhauer proposes a philosophical text^²⁰ that develops his conception of science as well as a programme for implementing this philosophy of science. It is a question of conceiving a kind of link between the concrete relationship to experience on which the sciences are based and the tendency towards abstraction in philosophical thought. Schopenhauer addresses this middle ground by positing that such a discipline “stands, therefore, in the middle between the particular sciences of which it is the philosophy, and Philosophy pure and simple, the philosophy of the world, which is the most general truth, the most general access to the whole of things, but which must also, in this sense, provide access to each individual thing”^²¹. Philosophy loses its position of superiority and descends from Cloudcuckooland [Wolkenkuckucksheim] to anchor itself more firmly on the ground of experience. At the end of this fragment, he concludes by emphasising that: “Moreover, this philosophy of the emerging science of nature does not belong primarily to Schelling, but to Kielmeyer and the progress of the time, particularly in France.” (HN III, [37], p. 88). This “philosophy of a science” thus initiates a general unification of experience and constitutes, if we extend the metaphor of the tunnel or the cave of Pausilippe, the true junction where the philosopher meets the scientist and where light finally passes from one side to the other. This intermediate philosophy contributes to the creation of a higher point of view: an “comprehensive view [Uebersicht]”, “the highest point of view [vom höchsten], “a general view [allgemeinen Ansicht]”, which makes it possible to overcome the infirmity of an analysis that is only abstract or too rooted in the field of science in order to finally discover the real essence of the world. Above all, we see that such a philosophy also constitutes a kind of compass in that it must be capable of confirming the great metaphysical theses. From this, we can better understand the role of the strange text On the Will in Nature, in which Schopenhauer, in 1836, reviews scientific progress in all fields in order to find agreement with his own theory of the will. In the same vein, the Supplements continue this idea, and Chapter 20 does not hesitate to draw a parallel between the conclusions of The World and the work of X. Bichat, thus corroborating (Bestätigung) his theses. More generally, the different versions of The World bear the marks of such a requirement. One need only glance at the layers of rewriting in the work to see that it is indeed Book II and its Supplements that have undergone the most extensive modifications and additions. Thus, for example, it is no less than the entire theory of the objectification of the will that is refined in the light of the scientific discoveries he compiled after 1819, with particular attention to French physiology. Once again, it is worth remembering that such interactions are implied by the very project of a metaphysics of experience.

This concern with developing a “philosophy of science” clearly attests to the importance that science had for him, but also to his early awareness of the scientific field's evolution towards total autonomy. Schopenhauer witnessed a shift that moved scientific practice from the academies to the universities – a shift whose effects he had already observed in France. This evolution led to the professionalisation of the sciences, which contrasted with practices that could now be described as amateurish. Schelling's Naturphilosophie and Goethe's practice belonged to an old world that would soon be viewed with amusement by those who, from 1834 onwards, would call themselves "scientists^²²". It is no coincidence that it was a philosopher with genuine scientific experience who was best able to consider such a phenomenon. It is important to emphasise Schopenhauer's particular lucidity, because the establishment of a true philosophy of science is often traced back to 1834 with André-Marie Ampère's short work entitled Essai sur la philosophie des sciences (Essay on the Philosophy of Sciences), or to 1840 with William Whewell's book The Philosophy of the Inductive Sciences, but we then forget that Schopenhauer set out his analyses in his Nachlass as early as 1821. Then, by changing the traditional relationship between the scientist and the metaphysician, Schopenhauer also sketched out the possibility of a new horizon for metaphysics.

By emphasising the influence of less philosophical figures on Schopenhauer's thinking, we wanted to show that the very development of his system is the result of an openness: Schopenhauer establishes a fair dialogue between scientists and philosophers, rather than a dispute. Thus, after celebrating the end of religion's tutelage over philosophy, he shows us that science, too, must conquer its autonomy from metaphysics. Such a project largely explains the ambiguity surrounding his relationship to Naturphilosophie in general and to Schelling's philosophy in particular. It is indeed interesting to re-evaluate, from this perspective, the relationship he may have had with Schellingian philosophy, looking beyond the impact of Philosophical Investigations into the Essence of Human Freedom (1809) on the development of the concept of will^²³. Schelling plays an essential role in showing that it is possible to go beyond Kant's understanding of science and its limitations and thus to make nature a scientific object in its own right. For the young student at the Göttingen Faculty of Medicine, it is an understatement to say that such a perspective is liberating. Above all, the model that Schelling outlines proposes a strong research programme by opposing a strictly mechanistic view of reality while avoiding falling back on classical dualism. Schopenhauer found in these works the possibility of a metaphysical monism that was entirely compatible with his own intuitions. Nevertheless, differences inevitably emerged as his own metaphysics took shape. The Nachlass bears witness to this distancing and shows, for example, how the notion of “force” seems obsolete to him (imported from the phenomenal world, such a concept cannot have any real metaphysical pretensions without falling into a whole series of contradictions). He also revisits the notion of “polarity”, which had nevertheless appealed to him during his early readings. But ultimately, what caused the most decisive break was the very nature of the relationship between science and philosophy, which led him to call for a true “philosophy of science”.

We are aware that Schopenhauer's criticism of Schelling is sometimes unfair, and it is clear that he partly misunderstands Schelling's project, but what he says about it, and the way in which he opposes it, implicitly outlines the very nature of what he intends to establish. Schopenhauer invites us to rethink the status of experience within metaphysics itself and therefore calls for a complementary, non-hierarchical relationship between science and philosophy. Once again, we owe it to Marco Segala for highlighting the decisive place of the natural sciences in the development of the system, but also, and perhaps above all, the evolution of their importance between the first and second editions – an evolution partly due to the consequences of the criticism levelled against Schelling's naturphilosophie. The unity of knowledge advocated by philosophers until then gradually fragmented in the face of evolving scientific practices, making the integration of their knowledge into a metaphysical project even more problematic. The writing of On the Will in Nature and a second volume of Supplements responds in part to these questions. If we return to our question of the Stufenfolge to illustrate this, we can only note the emergence of new obstacles – the most significant of which is linked to the theory of Ideas as developed in Book II of the first edition of The World. However, this theory, which was supposed to provide a stable ontological foundation for scientific theories, now encountered the difficulty of a temporalised vision of the Stufenfolge within the natural sciences, introducing a kind of break between the two. In short, the fundamentally timeless structure of his metaphysics found it increasingly difficult to find confirmation in scientific theories that increasingly emphasised the temporalisation of nature. The manuscripts of 1821 testify to Schopenhauer's embarrassment on this subject, but also highlight how it was these situations of deadlock that made it increasingly necessary for a philosophy of science to emerge, whose results could confirm metaphysical theses but also – as we see here – falsify them. Despite his aversion to Lamarck's transformism^²⁴, Schopenhauer gradually became aware of the central role of temporality in explaining many biological processes and gradually replaced Ideas with a will that could now objectify itself without intermediaries in natural forces and species^²⁵, thus confirming a real change in the relationship between science and philosophy. Thus, despite his clearly expressed desire in the prefaces to present his system as immutable, Schopenhauer did not hesitate to revise it. Far from being a flaw, this, in our view, demonstrates Schopenhauer's concern to remain grounded in experience and, therefore, his distrust of the seductive power of abstraction, which, by detaching itself from experience, immunises itself against any contradiction. This danger worries him because it is precisely the one on which, in his view, Naturphilosophie has foundered. The aim, therefore, is to guard against this by establishing a genuine dialogue with the sciences, as this is the only viable way to attempt to restore a true metaphysics, i.e. a metaphysics that does not think itself against the world, but rather within the world.

DEUSSEN, P. Les Éléments de la métaphysique, trans. fr. E. Nyssen, Paris : Perrin et Cie, 1899.

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KIELMEYER, C. F. Ueber die Verhältniße der organischen Kräfte unter einander in der Reibe der verschiedenen Organisationen, die Geseze und Folgen dieser Verhältniße, Marburg : Basilisken-Presse, 1993. English translation in Kielmeyer and the Organic World, L. Azadpour & D. Whistler (éd.), London: Bloomsbury, 2021.

LOVEJOY, A. O. “Schopenhauer as an Evolutionist”, The Monist, Volume 21, Issue 2, p. 195-222, April 1911.

SCHOPENHAUER, A. Der handschriftliche Nachlaß, hrsg. A. Hübscher, DTV Klassik, Munich, 1985, 5 volumes.

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SCHOPENHAUER, A. Le Monde comme volonté et représentation, ed. C. Sommer. Paris : Gallimard, 2009, 2 volumes.

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PhD in Philosophy, teacher in preparatory classes (CPGE), and lecturer at the University of Poitiers

Batini, U. Schopenhauer: the awakening of experience against the dreams of Naturphilosophie. Voluntas: International Journal of Philosophy, Santa Maria - Florianópolis, v. 17, n. 1, e94445, p. 01-21, 2026. Available at: https://doi.org/10.5902/2179378694445.

2 In 1820, in issue 7 of the journal Hermes oder kritisches Jahrbuch der Literatur, Johann Friedrich Herbart, who at that time held Kant's chair in Königsberg, published a long critical review of The World and his doctoral thesis On the Fourfold Root of the Principle of Sufficient Reason, which he reread in the light of the opus magnum. He attempted to determine Schopenhauer's place in relation to Kant's various successors and emphasised that Schopenhauer was undoubtedly the clearest and most skilful.

4 Schopenhauer, A, Der handschriftliche Nachlass, Arthur Hübscher , ed., Munich, DTV Klassik, 1985, vol. III, Brieftasche, § 38, pp. 152-153 (hereinafter cited as HN followed by the volume number, fragment number and page number): “Metaphysics would then belong to the a posteriori sciences, that is, to the empirical sciences. [...] We must therefore resign ourselves to counting metaphysics among the empirical sciences. But its peculiarity is that it connects inner experience with outer experience and that its foundation is not a particular experience, but the most general experience. Metaphysics is therefore only the correct conception of experience as a whole, and not in its details. […] The object of metaphysics is not this or that experience, as is the case with all other sciences, but experience in general, experience as such. [Danach würde dann Metaphysik zu den Wissenschaften a posteriori, also zu den Erfahrungswissenschaften gehören. […] Wir müssen uns also bequemen Metaphysik zu den Erfahrungswissenschaften zu rechnen. Aber ihr Eigentümliches ist: sie verbindet die innre mit der äußern Erfahrung und ihr Fundament ist keine besondere, sondern die allgemeinste Erfahrung. Metaphysik ist sonach bloß die richtige Auffassung der Erfahrung im Ganzen, nicht im Besondern. [...] Der Gegenstand der Metaphysik ist nicht diese oder jene Erfahrung, wie dieses bei allen andern Wissenschaften der Fall ist; sondern die Erfahrung überhaupt, die Erfahrung als solche.“]

12 See E. Kant, Metaphysical Foundations of Natural Science (1786), Ak. IV, 468, OP II, p. 365: "But if the foundations or principles found therein are ultimately purely empirical, as in chemistry for example, and if the laws by which the given facts are explained by reason are mere laws of experience, these foundations and laws do not entail any awareness of their necessity [...], and consequently this whole does not strictly deserve the name of science; chemistry should therefore be called a systematic art rather than a science."

16 Schopenhauer, A. W I, § 28, p. 220: "Just as knowledge of the unity of the will as a thing in itself in the infinite variety and diversity of phenomena alone provides the true explanation for this marvellous analogy, impossible not to recognise among all the productions of nature, this family resemblance that allows us to consider them as variations on the same theme, which would not be given; so too, through a clear and profound understanding of this harmony, this essential coherence between all parts of the world, this necessity for their gradation, which we have just considered, a true and sufficient understanding of the intimate essence and meaning of the undeniable FINALITY of all organic products of nature will open up to us, a finality which, consequently, we also presuppose a priori when we examine and judge these same products.”

18 Schopenhauer laments in his notebooks that whenever we cannot find a cause, we posit a force. See HN II, p. 320: "We are obliged to stop at forces, because the category of causality seeks to satisfy itself in an ascending line, that is, it progresses from effect to cause: where it can no longer find the cause, we insert a force, that is, in fact, an imagined intermediary between the cause and the effect, which we use as a substitute for the unknown cause that is at the basis of the last known effect; so to speak, a mark that we attach to indicate how far we have advanced in our recourse.” This force implies stepping outside the framework of science and conducting a metaphysical investigation. He will return to these arguments in paragraphs 14 and 15 of Book I of The World, but also in Book II, when he makes the forces of nature an immediate objectification of the will.

19 The violence of his attacks is actually moderate compared to some that sometimes emanate from the scientific world, such as Johann Ludwig Choulant (1791-1861), who does not hesitate to assert that naturphilosophie is a "mixture of fiction and truth, poetry and science, this way of playing with empty, half-true analogies, this way of supposing and suggesting rather than knowing and understanding has ruined our German reputation abroad and distanced us from rigorous science." (See Ludwig Choulant, "Versuch über Ludwig Wilhelm Gilberts Leben und Wirken", Annalen der Physik, 1824 (76/4), pp. 453-471, pp. 468-469).

20 Foliant I (1821) – HN III, [37], p. 86 et seq. This note clearly reveals the organisation and purpose of the 1836 work, On Will in Nature.

Philosophy of a science is a relative and comparative philosophy, whereas philosophy pure and simple, that is, the philosophy of existence in general, is an absolute philosophy. The former is in fact the comprehensive view of the main results of a science, taken from the highest point of view, that is, the most general possible within that science. It is the unification of the main results of science in a general view of its object that at the same time provides the true method for the manipulation of such a science. This general vision is a philosophical vision, precisely because it is general. It is therefore what will be immediately linked to philosophy as such, if there is to be one, and in the meantime presents itself as a datum for such a philosophy, as a given that has already been worked on and is ready, saving its author the trouble of going down to the raw material. It therefore stands in the middle between the particular sciences of which it is the philosophy, and philosophy pure and simple, the philosophy of the world, which is the most general truth, the most general access to the whole of things, but which must also, in this sense, provide access to each individual thing.

The philosophy of each science does not need the endorsement of philosophy as such, for it is discovered independently of it and is based on induction from its own science. For this reason, it will always correspond to true philosophy as such, whatever form the latter may take. Conversely, philosophy as such must be confirmed by each philosophy of a particular science, insofar as the most general truth is related to more particular truths and is illuminated by them.

From this point, the philosophies of particular sciences can already be developed, before a philosophy as such is given; and when it does arise, these will always be adapted to it.

Universidade Federal de Santa Maria

Voluntas, Santa Maria, v. 17, n. 1, e94445, 2026

DOI: 10.5902/2179378694445

ISSN 2179-3786

Received: 11/18/2025 • Accepted: 06/26/2026 • Published 07/25/2026

XI International Schopenhauer Colloquium

Schopenhauer: the awakening of experience against the dreams of Naturphilosophie

Schopenhauer: o despertar da experiência contra os sonhos da Naturphilosophie