Lebenskraft (Vital Force)

Although it gained currency in scientific debates about generation and processes of life (vitality) at the end of the eighteenth century, the lexeme Lebenskraft (vital force) played only a marginal role in Goethe’s scientific writings. By accounting for the distinctiveness of the living (or organic, animate), it manifests the conceptual bifurcation within the scientific discourse of the period between the living and non-living. Goethe’s understanding of the concept, which is fluid, reflects a critical approach to these debates. While at times he understood Lebenskraft as an organizing principle to explain processes of generation, he was generally skeptical toward the concept, which in his view compromised scientific argumentation and limited knowledge production. In Goethe’s literary works, by contrast, Lebenskraft, became a positive metaphor for metaphysical and artistic acts of creation.

  1. Introduction
  2. Lebenskraft and Spontaneous Generation
  3. Metacritical Approaches to Scientific Argumentation
  4. From Lebenskraft to Form
  5. Forces, Drives, and Theories of Generation
  6. The Aesthetics of Lebenskraft
  7. The Metaphysics of Creation
  8. Conclusion
  9. Notes
  10. Related Entries in the GLPC
  11. Works Cited and Further Reading


Goethe’s shifting understanding of Lebenskraft can be productively elucidated by considering it in the context of the conceptually fluid scientific discussions of his day. Situated at the juncture of scientific, medical, and philosophical thought at the end of the eighteenth century, the concept had become the subject of intense polemical debates in the 1790s. Goethe’s engagement with Lebenskraft, however, which reflects an uncertainty in the newly emerging life sciences at the turn of the nineteenth century about its own foundational principles, remained at the margins of the debate. Within his later morphological studies, moreover, it eventually replaced generative principles of development and force with certain formal structures like “Metamorphose” (metamorphosis).1 In fact, the physician Johann Dietrich Brandis (1762–1846) even suggested a reverse influence: Goethe’s debut as a plant morphologist with Versuch, die Metamorphose der Pflanzen zu erklären (1790; Essay Explaining the Metamorphosis of Plants), according to Brandis, had actually inspired his own thinking in his treatise on Lebenskraft (FA 1.25:770).2

Alongside cognates such as nisus formativus and Bildungstrieb (formative drive) in Johann Friedrich Blumenbach (1752–1840) or vis essentialis in Caspar Friedrich Wolff (1733–1794), at stake in the discussions around Lebenskraft are (1) the ontological question of what life or vitality actually is and (2) the methodological question of what the appropriate organizing principle for experimental investigations of living phenomena should be.3 Historians of science have pointed to the prominence and proliferation of the scientific debates about vital forces towards the end of the eighteenth century,4 which were embedded in the opposing theories of epigenesis and preformation elaborated by Wolff and Blumenbach in their respective treatments of vis essentialis and Bildungstrieb. Wolff’s embryology proposed essential force to account for the source of organized development in animal and plant bodies.5 His link between vital forces and theories of organic development in embryology is equally important for a discussion of Goethe’s use of Lebenskraft, which is primarily negative and tantamount to a rejection of the concept as used in the debates of the 1790s.6 While Lebenskraft enjoyed its greatest popularity at the turn of the nineteenth century, moreover, Goethe was not alone in his skepticism. Schelling, in particular, considered the concept to be unproductive, not least because it posited a hidden force at work in living organisms that could not be empirically verified.7 And it is precisely this kind of skepticism that moved Goethe to privilege formal structures like Typus (type), Urbild (primal image), and Metamorphose (metamorphosis) over functional principles or postulates like Lebenskraft, which understand form as both passive and subsidiary to life conceived as a power or force.

Importantly, and in contrast to the ontological debates, Goethe’s account of Lebenskraft allowed him to position his morphology as a methodological innovation and response to the problems that Lebenskraft was supposed to solve. Within the sciences of physiology, medicine, and botany, in fact, Lebenskraft was already a capacious term that could be employed as a heuristic device, as Goethe also did, predominantly in his own his scientific writings. Because the concept is flexible and suggestive of protean vitality, however, it became especially productive in poetic works like Dichtung und Wahrheit (1811–1833; Poetry and Truth) and Wilhelm Meisters Wanderjahre (1821/29; Wilhelm Meister’s Journeyman Years).8

Since Goethe’s engagement with the discussion about Lebenskraft among his contemporaries was at times ambivalent, it is worth further considering the historical context of the so-called Lebenskraft debate. The fundamental question that animated the controversy was: “what constitutes life?” The word Kraft—which can be variously rendered as force, power, or capacity9—acted as a placeholder for vitality that spoke to the problem of defining organisms or organized bodies. But Kraft also reflected the role of force in the physical sciences of the time, such as heat in chemistry and gravity in physics.10 By conceptualizing the innate agency of organic life as a physical force or power, then, Lebenskraft intervened in eighteenth-century debates around the relationship between matter and activity,11 thereby reflecting the need for discursive constructs in the nascent life sciences and scientific vitalism, which, broadly speaking, proposed various self-organizing and goal-directed forces immanent to living matter.12 Within highly speculative debates about organisms and their inherent forces, moreover, Lebenskraft could be flexibly employed. Rather than referring to an overarching principle of organization, it was commonly considered in the plural as Lebenskräfte (as in Blumenbach), where each distinct force was associated with discrete functions in nutrition, generation, and, where possible, regeneration.13

While vitalist theories met with skepticism precisely because they presupposed an irreducible but non-verifiable force at work, the strength of the polemics around Lebenskraft at the end of the eighteenth century also suggests a move away from Cartesian mechanism that augured the establishment of biology as a discipline at the turn of the nineteenth century. With the exception Leibniz’s vis viva (for which a fully mechanist account of nature included an immaterial force), mechanism generally construed matter as predominantly devoid of any indwelling active principle.14 As such, it further required the intervention of a divine creator who set mechanical forces in motion. Once the theological underpinning of a mechanistic worldview was abandoned, however, agency, or even the will, could be naturalized and given conceptual shape as forces or drives.15 Ultimately, then, Lebenskraft made manifest the conceptual need to distinguish between organic and inorganic bodies and to differentiate between the animate and inanimate, as well as the living and the non-living. Typically, it functioned as a means to examine the properties of organic bodies that could not be explained mechanically and also could not be accounted for by physical and chemical laws. Rather than serving a regulative or constitutive principle, Lebenskraft was predominantly understood as a causal agent within the processes of a living body.

The conceptualization of Lebenskraft as causal agency involved a variety of tensions: between, for example, potentiality and actuality, or the living and non-living, or the organic and the inorganic. But as with Kraft, its ontological status remained unsettled. Broadly speaking, Lebenskraft referred to a dynamic life principle, but what remained unclear was whether—in philosophical terms—it was something material or immaterial or an active element within substance.  Nor could science settle the question of its grounding in chemical or bioelectrical processes or, distinct from both of these, whether it could treat it as something irreducibly biological.16 In short, Lebenskraft remained—in the concise formulation of Eve-Marie Engels—a “Lückenparadigma” (gap paradigm), that encouraged ongoing theoretical speculation about the conceptual specificities of living phenomena.17

Lebenskraft first emerged in physiological and medical debates in the latter half of the eighteenth century. One of its earliest configurations in this context was in Friedrich Casimir Medicus’s tract Von der Lebenskraft (1774; On Vital Force), which describes it as a material-spiritual substance connecting organized matter to the individual soul. The word itself, however, was less a neologism than a translation of vis vitalis, or dynamic life principle, which has a long philosophical genealogy.18 In addition to Aristotle’s pneuma,19 it has been variously linked to Stoic cosmology, Galenic vital heat, Paracelsus’s archaeus , Jan van Helmont’s Paracelsan theory of animate life, and—at the turn of the eighteenth century—Georg Ernst Stahl’s notion of an anima sensitiva.20

An important precursor for the polemical tracts of the 1790s—as well as for Goethe’s thinking about Lebenskraft—was Albrecht von Haller, whose physiology naturalized vital forces. In the 1750s Haller had proposed two fundamental forces in organisms: Sensibilität (sensibility), which he related to the responses of nerves to external stimuli and how they are transmitted to the brain, and Irritabilität (irritability), which he treated as a capacity within muscle and plant fibers. The consistent recourse to Haller—alongside a concomitant interest in John Brown’s medical discussion of excitability—became symptomatic in discussions about the specific properties of animal and plant life and their connection to vital force(s) in both physiology and medicine.

A focal point for the debates around Lebenskraft in the 1790s was the University of Göttingen, where Haller and Blumenbach both held positions.21 In Steigerwald’s detailed reconstruction of these debates, Lebenskraft reached the height of its popularity around 1795, when a number of publications appeared that argued for a vital force at work throughout organic bodies. But the discussions had already been stimulated in part by Christoph Girtanner (1760–1800), who also had studied at Göttingen and in 1790 published his Abhandlungen über die Irritibilität als Lebensprincip in der organisierten Natur (Treatise on Irritability as a Principle of Life in Organized Nature).22 And when, during the 1790s, Goethe’s interest in the concept expanded, he not only returned to Blumenbach,23 but also supplemented his studies with Carl Friedrich Kielmeyer (1765-1844), whose influential Über die Verhältnisse der organischen Kräfte untereinander in der Reihe der verschiedenen Organisationen (1793; On the Interrelationships of Organic Forces in a Series of Different Organisms) treats a series of five vital forces.24 Additionally, both Goethe and Schiller consulted with physicians who themselves contributed to the debate around vital forces, most notably Christoph Wilhelm Hufeland (1762–1836) and Samuel Thomas von Sömmerring (1755-1830).25 And Goethe himself chaired the meeting of the short-lived Gelehrten-Verein or Freitagsgesellschaft (Learned Society or Friday Society) in March 1792, where Hufeland gave a lecture on the philosophical and conceptual problematics of Lebenskraft that also presented it as an essential component of organic life along with light, warmth, and air (LA 2.9A:41112).26

Lebenskraft and Spontaneous Generation

When Goethe considered  Lebenskraft in his scientific writings,  he understood it, almost exclusively, in terms of generative processes in organic bodies—animals, insects, and most commonly, plants. His comments are for the most part at the margins of his writings, however, and often in truncated notes, where the concept is deployed suggestively but rarely elaborated. With the exception of his botanical studies, moreover, Goethe’s marginal consideration of Lebenskraft is in line with the tenor of the debates in the 1790s, where the concept is deployed as a placeholder in the context of the reciprocal processes of generation and degeneration in plants and animals to explain how bodies achieve and maintain their organization. In his scientific studies on plant physiology and plant and insect metamorphosis, however, as well as in his literary works, Goethe more explicitly lays out a teleological linearity for Lebenskraft that he associates with the generation of specific organisms. Here we can also find the concept bound to the problem of the boundary between the living and the non-living, especially in the studies that fall between botany and zoology. Prior to his Italian journey, in fact, Goethe had already developed an interest in microscopic animalcules or effluvia (bacteria and protozoa), and he even carried out experiments on animal and plant infusions in 1786.27

The impetus for these investigations was the theory of spontaneous generation, or heterogenesis, which argued that living beings can be generated from non-living organic matter.28 And the theory continued to engage Goethe, whose truncated notes from the mid- to late 1790s on the physiology of heterogenesis  reconsider his experiments with animal and plant infusions from the 1780s to speculate on how Lebenskraft and spontaneous generation intersect. Goethe’s notes to himself were stimulated by a report, dated 1778, by a professor of natural history at Göttingen, Christian Wilhelm Büttner (1716-1801), who had conducted an experiment over several months on a tree frog confined to a sealed cylinder half-filled with rainwater (LA, 2.9B:40). Büttner observed how the frog had shed its skin and the animalcules in the glass cylinder had appeared to proliferate as the shed skin disintegrated. Goethe's notations some twenty years later took up Büttner’s suggestion of a correlation between non-living matter and the generation of animalcules by considering the relationship as potentially causal:

Nachwirken der Lebenskraft sich zu organisieren
Schimmel auf Pflanzen und Thierkörpern
Infusions Thiere
Intermediäre Naturen möglichkeit des ergreifens und Zueignens. (LA 2.9B:40)
the continued effect of Lebenskraft organising itself
Mold on plants and on animal bodies
Intermediary natural beings, [the] possibility of grasping and assimilating.

These observations proceed associatively from Büttner’s report: Lebenskraft assumes a function that first stresses the nexus of generation and degeneration, rather than one that just describes a specific organism and its generation. Beyond the death of a given organism, moreover, and conceptualized as an organizing principle, the force allows for the generation of new organisms from non-living matter, whether in the process of biodegradation or even in the symbiotic connection between mold or fungi on plants and animal bodies. Animalcules occupied a doubly liminal space in scientific thought of the time—not only by appearing on the boundary between the living and the non-living, but also as organisms situated between botanical and zoological orders.29  Accordingly, by focusing his attention on the dynamic status of these intermediary creatures and the animalcule’s capacity to appropriate non-living organic matter as part of the process of organic generation, Goethe has begun to conceptualize Lebenskraft as something hypothetically productive. At least in his preliminary thinking about the concept, and in its relation to spontaneous generation, it emerges as an organizational principle that operates between individual organisms.

Metacritical Approaches to Scientific Argumentation

The explication of Lebenskraft in Goethe’s physiological notes raises the question of why his overall stance towards the concept should be skeptical to the point of rejection. The problem with Lebenskraft, it appears, is primarily a metacritical or methodological one that is embedded in Goethe’s philosophy of science. It separates into distinct questions: (1) how to translate the hypothesis of Lebenskraft into empirical practice and (2) how to assess its usefulness in relation to the methodological and theoretical requirements of scientific discourse. In Betrachtung über Morphologie überhaupt (1794; Observations on Morphology in General), Goethe systematically examines modes of scientific thinking ranging from natural history and Naturlehre (theory of nature) to anatomy, physics, and chemistry, as well as zoonomy, or the study of functions in an organic body. In both physiology and zoonomy, we are told in Goethe’s discussion of the latter, the presence of a fundamental spiritual or physical force becomes part and parcel of conventional habits of thought in vitalist theories:

in so fern die Naturen organisiert sind, und sie nur  durch den Zustand, den wir das Leben nennen, organisiert und in Tätigkeit erhalten werden können: so war nichts natürlicher, als daß man eine Zoonomie aufzustellen versuchte und denen Gesetzen, wornach eine organische Natur zu leben bestimmt ist, nachzuforschen trachtete; mit völliger Befugnis legte man diesem Leben, um des Vortrags willen, eine Kraft unter, man konnte, ja man mußte sie annehmen,  weil das Leben in seiner Einheit sich als Kraft äußert,  die in keinem der Teile besonders enthalten ist. (FA 1.24:367)
Given that natural entities are organized and require the condition we call life to be organized and to remain active, nothing was more natural than that a science of physiology should be established in an attempt to discover the laws an organism is destined to follow as a living being. For the sake of argument this life was quite properly viewed as derived from a force, an assumption that was justified and even necessary because life in its wholeness is expressed as a force not attributable to any part of the organism. (Miller, 59)30

When working through the logical inferences of scientific discourse and its arguments here, Goethe speaks in a tone that is both analytic and cautious. And while he stops short of using the term, he points indirectly to the conceptual problem of Lebenskraft as the more general problem of causality. As a byproduct of disciplinary habits, it can only outline natural phenomena by referring to a generalized causal agent whose analytical value lies in accounting for the distinctiveness of living organisms.

Goethe himself had made use of similar nomenclature in the closing summary of Versuch, die Metamorphose der Pflanzen zu erklären, which offers a detailed account of plant metamorphosis in the systematic attempt to explain botanical development through a chronological narrative. Here the term Lebenskraft is conceptually grounded in the activities of growth and reproduction, which for Goethe are the dual expressions of the force that stimulates metamorphosis:

Betrachten wir eine Pflanze in sofern sie ihre Lebenskraft äußert, so sehen wir dieses auf eine doppelte Art geschehen, zuerst, durch das Wachstum indem sie Stengel und Blätter hervorbringt, und sodann durch die Fortpflanzung, welche in dem Blüten- und Fruchtbau vollendet wird […] Diese sprossende, nach und nach sich äußernde Kraft ist mit jener, welche auf einmal eine große Fortpflanzung entwickelt, auf das genauste verwandt. (FA 1.24:148-49).
If we consider the plant in terms of how it expresses its vitality, we will discover that this occurs in two ways: first, through growth (production of stem and leaves); and secondly, through reproduction (culminating in the formation of flower and fruit). […] The power shown in gradual vegetative growth is closely related to the power suddenly displayed in major reproduction. (Miller, 95-96)

Interestingly, Goethe here falls into the same habit of thought that he would later criticize in scientific discourse. Rather than postulating a vital force per se as a necessary condition of his argument, Goethe rhetorically deploys and reifies vitalist elements in his language without reflecting on how Lebenskraft can adequately describe or analyze the activities of organic bodies. That is to say, he simply foregrounds the interconnected processes of growth and reproduction as creative expressions of the productivity of life without considering what underlies the processes of change that inform all living forms as such.31

From Lebenskraft to Form

In dialogue with Alexander von Humboldt (1769–1859), Goethe would develop a metacritical and philosophically more nuanced analysis of Lebenskraft that eventually allowed him to understand the marginal character of Lebenskraft in his own botanical thinking. In fact, as certain diary entries suggest—which note receipt of a treatise by the Danish physician Joachim Dietrich Brandis (1762–1846), as well as Hufeland’s Ideen über Pathogenie und Einfluß der Lebenskraft auf Entstehung und Form der Krankheiten (1795; Ideas on Pathogenesis and the Influence of Vital Force on the Development and Form of Illnesses)—Goethe was becoming increasingly aware of the scientific and medical aspects of the debates around Lebenskraft. And while neither Brandis nor Hufeland left substantive traces on Goethe’s thoughts about it as either a scientific or philosophical concept, Humboldt served as a useful interlocutor in the development of his nascent theory of plant morphology in the 1790s.

In his early work, Humboldt had experimented with the concept of Lebenskraft, but he would later come to abandon it.32 Thus, predominantly in Aphorismen aus der chemischen Physiologie der Pflanzen (1794; Aphorisms on the Chemical Physiology of Plants, a German translation of the second part of the 1793 work Florae fribergensis specimen, plantas cryptogamicas), he made recourse to Lebenskraft as a force or power that animates and organizes bodies. But he also popularized and reworked the concept in his sole literary work, a short poetic allegory for Schiller’s Horen (The Horae) entitled “Die Lebenskraft oder der rhodische Genius” (1795; Vital Force or the Rhodian Genius). While it had become possible in the physiology of the late eighteenth century to identify individual elements in organisms, such as oxygen and nitrogen, that contribute to the maintenance of their when alive, the same elements would paradoxically also facilitate degeneration and decomposition upon death. Humboldt’s early discussion of Lebenskraft had attempted to account for this paradox by proposing that the force prevented individual elements from re-organizing themselves according to the conventional affinities of chemical elements in animal and plant matter, thereby suspending putrefaction or decomposition in organic bodies.33 This could also account for the compositional differences between animate and inanimate bodies. But in “Lebenskraft” he would assign it a double function, as detailed by the ancient Greek natural philosopher Epicharmus, whom the allegory uses as device to offer an interpretation of two statues that symbolically embody Lebenskraft. The first image is authoritarian: Lebenskraft forcibly suspends the bonds of chemical affinities found in inorganic material and causes the elements to re-arrange themselves into organic, animate matter:

Erkennet im rhodischen Genius […] im Herrscherblick seines Auges das Symbol der Lebenskraft, wie sie jeden Keim der organischen Schöpfung beseelt. Die irdischen Elemente zu seinen Füßen streben gleichsam ihrer eigenen Begierde zu folgen und sich miteinander zu mischen. Befehlend droht ihnen der Genius […] seinem Gesetze zu folgen.34
see in the Rhodian Genius, […] in the regal glance of his eye, the symbol of the Life Force and how it animates every particle of organic creation. The earthly elements at his feet seem to strive to follow their own desires and to join together. Commandingly, the Genius threatens them […] to follow his laws (Person, 264).35

While this action explains the generation of organic matter and elucidates how Lebenskraft functions as a sustaining force, it is also tantamount to stasis and cannot account for processes of degeneration—or, by extension, for processes of generation thereafter. This is where Humboldt’s second image, together with the second function of Lebenskraft, become important in his allegory. Indeed, the second image explores the dialectical character of Lebenskraft as an agency that oscillates between orderly stasis and chaotic freedom:36 “Der Fesseln entbunden, folgen sie wild nach langer Entbehrung ihren geselligen Trieben; der Tag des Todes wird ihnen ein bräutlicher Tag.—So ging die tote Materie, von Lebenskraft beseelt, durch eine zahllose Reihe von Geschlechtern”37 (Person, 264; The shackles now loosened, they wildly pursue, after long deprivation, their drives to unite; the day of death is for them a wedding day.—Thus does dead material, animated by the Life Force, go through an innumerable succession of generations). While it might appear curious for Humboldt to refer to social affinities and erotic attractions to express the idea of Lebenskraft as it negotiates the nexus of life and death, his language neatly maps onto the imbrication of sympathy and theories of palingenesis or metempsychosis at the close of the eighteenth century.38 In the Aphorismen, in fact, Humboldt had already conceded—in the wake of Haller—the difficulty of quantifying Lebenskraft, which works hand in hand with irritability in animate bodies and appears to be based in the cell tissue, or the sap and air vessels (vasa spiralia) of plants, as well as in the blood of animals (Humboldt, Aphorismen, 30–33).

Goethe’s criticism of Humboldt took shape in his notes from 1796, which focus  on how his interlocutor’s conceptual reliance on Lebenskraft compromises the line of his argument. Comparative analysis, according to Goethe, led Humboldt away from sustained empirical investigation:

Welcher Umschweif Holz und Knochen immer zu vergleichen um zu sagen daß sie nichts mit einander gemein haben als pp. was doch nicht wahr ist.
Das ganze ist nur die Ausschweifung um seinen Satz was Lebenskraft wircke allgemein zu machen. Weil die Knochen sich nach dem Tode nicht dekompiniren so müssen sie beym Leben auch nicht belebt seyn!! (LA 2.9B:14)
What a circumlocution it is to constantly compare wood and bones only to say that they do not have anything in common other than etc., which is of course not true.
This is all just a digression to make the proposition of what Lebenskraft effects generally valid. Because bones do not decompose after death does not mean that they cannot also be animate during life!!

Humboldt’s argument, according to Goethe, is predicated on a comparison between wood and bones as inanimate parts of otherwise animate beings. Both are inanimate, because neither is subject to decomposition, which constitutes one of Humboldt’s preconditions for animate matter to contain Lebenskraft. Goethe’s increasing frustration is twofold. Humboldt overlooks the distinction between zoology and botany, and Goethe suspects that such analogical thinking is overly determined by the postulate of Lebenskraft. For this reason, the comparison between animals and plants reveals little apart from Humboldt’s need to make Lebenskraft a functional organizing principle.

In finding Humboldt’s argument lacking, Goethe’s metacritical analysis is symptomatic of a wider problem of legitimacy in the processing of scientific knowledge in the period: there were few regulations and formalized methods for how knowledge should be produced, how empirical evidence should be used, or what styles of argument should be deemed acceptable.39 This methodological fluidity also allowed Goethe to intervene in scientific debates. In an earlier note from 1794, Goethe had already framed his own morphological project, with its focus on form,40 as a response to different, but interrelated, models of scientific explanation:

Zu allererst recht zu überdenken wie man sich in die Mitte zwischen die Erklärungsarten setzt. Zwischen
die mechanische
— chemische
— lebenskraftlich-chemische
— ––––––––––––––geistige
Sich deutlich zu machen daß sie alle und noch mehrere nicht hinreichen die Wirkungen des Lebens auszudrücken.
Meiner Darstellungsart der Form mit diesen Erklärungsarten zu Hülfe zu kommen. (LA 2.9A:227-28)
In the first instance, consider carefully how to position oneself at a point of equidistance between these types of explanation. Between
the mechanical
— chemical
— ––––––––––––spiritual
Make it clear that these and further types of explanation are not sufficient to express the effects of life.
To use these types of explanation to come to aid of my description of form.

In Goethe’s view, varying interpretations of Lebenskraft—whether associated with chemical or electrochemical activity or with a spiritual or metaphysical principle imputed to matter—are insufficient by themselves, as are mechanical or chemical attempts to explain the organization of organic bodies. At the same time, however, Goethe sees these interpretations as opportunities for developing his own ideas about form and morphology. And while the manner of his argument remains apodictic in these notes, Goethe casts himself as a synthesizing figure between overlapping modes of explanation.41 In fact, his note contains in nuce the structure of the later essay “Bildungstrieb” (1820; Formative Drive) from the Hefte zur Morphologie (1817–1824; Morphological Notebooks), where Goethe returns to his self-construction as a scientific mediator. Before turning to this essay on eighteenth-century theories of generation, however, it is worth mentioning that Goethe also makes positive use of Lebenskraft in his own scientific writings. Thus, while denying the concept any explanatory power, he occasionally made non-generalized use of it  by linking it to specific, empirically observed qualities of a given plant or insect, such as the “gewaltige Lebens- und Vermehrungskraft” (FA 1.15.1:404; tremendous vital and propagative force) of a wild carnation that he had observed during the Italian journey in July 1787 or, in his entomological studies, the vigorous activity in flight and otherwise of a convolvulus hawk-moth (FA 1.24:322). Even a date palm seed, he observed, has the capacity to germinate long after it has been extracted from the plant (FA 1.24:70). Even shorn of its status as a postulate or causal agent, Lebenskraft, it seems, can still assume a descriptive function.

Forces, Drives, and Theories of Generation

While the essay “Bildungstrieb” does not directly address Lebenskraft, by elucidating Goethe’s reservations about modes of argumentation in scientific theories of generation, it nonetheless offers an instructive parallel. Prompted by Kant’s praise of Blumenbach’s Bildungstrieb in the Kritik der Urteilskraft (1790; Critique of the Power of Judgment), the essay, which moves through variants of epigenetic theories from Wolff’s embryology to Blumenbach’s Bildungstrieb, is more wide-ranging than its title suggests. Goethe’s critique emerges from the difficulties he encountered with Wolff’s vis essentialis, which was conceptualized as a force to explain how a nascent plant or animal comes to organize itself:

Ausdrücke dieser Art ließen noch einiges zu wünschen übrig, denn an einer organischen Materie, und wenn sie noch so lebendig gedacht wird, bleibt immer etwas Stoffartiges kleben. Das Wort Kraft bezeichnet zunächst nur etwas Physisches, sogar Mechanisches, und das was sich aus jener Materie organisieren soll bleibt uns ein dunkler unbegreiflicher Punkt. Nun gewann Blumenbach das Höchste und Letzte des Ausdrucks, er anthropomorphisierte das Wort des Rätsels und nannte das wovon die Rede war, einen nisus formativus, einen Trieb, eine heftige Tätigkeit, wodurch die Bildung bewirkt werden soll. (FA 1.24:451)
This type of terminology proved unsatisfactory, for there is always a material quality about an organic substance, regardless of how much life we impute to it. In the first instance the word “force” means something purely physical, even mechanical; the question of what is to be formed out of that substance remains obscure and insoluble. Blumenbach then achieved the ultimate refinement of this term: he anthropomorphized the phrasing of the enigma and called the object of discussion a nisus formativus, an impulse, a surge of action which was supposed to cause the formation. (Miller, 35)

Goethe rejects Wolff’s vis essentialis, which falls short because it is both too material and too mechanical. Where Blumenbach succeeds is in moving away from material or mechanical causes, instead offering a principle that returns to Aristotelian habits of thought by having activity (“Tätigkeit”) interact with an underlying substance as co-determining aspects of organization.42 At the essay’s conclusion, Goethe endorses Blumenbach’s Bildungstrieb, but he also moves away from vitalist terminology altogether by subsuming it under the formal, organizing principle of metamorphosis.43 Indeed Goethe conceives of metamorphosis as offering a fuller appreciation of the Bildungtrieb. It is through intimate observation of the transformations in nature that the freedom of the Bildungstrieb becomes manifest: “So viel aber getraue ich mir zu behaupten, daß wenn ein organisches Wesen in die Erscheinung hervortritt, Einheit und Freiheit des Bildungstriebs ohne den Begriff der Metamorphose nicht zu fassen sei” (FA 1.24:452 and Miller, 36; I will go so far as to assert, however, that when an organism manifests itself we cannot grasp the unity and freedom of its formative impulse without the concept of metamorphosis).

Significant in Goethe’s move to metamorphosis—as with the move to form in his notes on Humboldt’s Aphorismen—is its focus of scientific thought on emergent life as a process, or as elaborated in Betrachtung über Morphologie überhaupt (1794; Observation on Morphology in General), as a dynamic condition, rather than a force. As Eckart Förster has outlined, without the trappings of causal or teleological thought inherent in Blumenbach’s Bildungstrieb, Goethe’s methodology for the perception of metamorphosis was founded on fusing an appreciation of the whole with a concomitant awareness of its constant mutability.44

Whereas Humboldt’s Lebenskraft is deficient in its excessive control of argument and analysis, Goethe’s more critically-aware approach to epigenesis and preformation in “Bildungstrieb” is founded in part on their metaphysical premises. The former, he argues, depends on a divine creator, who provides the impulse for activity in nature, while the latter transfigures activity and substance (or Spinozan natura naturans) into a god-like figure (FA 1.24:451-52). By excavating the premises of these scientific postulates and theories, Goethe is pointing (albeit negatively) toward an alternate, more naturalist, philosophy of science45 that is closer to his principle of “zarte Empirie” (FA 1.13:149; tender empiricism), which combines intimate observation of natural phenomena with the self-aware subjectivity of an observer.

The Aesthetics of Lebenskraft

As critical as Goethe was of Lebenskraft in a scientific context and while it remained marginal across his literary work, it nonetheless became productive in aesthetic and metaphysical contexts. In the second chapter of Wilhelm Meisters Wanderjahre (1821/29; Wilhelm Meister’s Journeyman Years), “Sankt Joseph der Zweite” (St. Joseph the Second), for example, which was first published as a novella in 1810, Wilhelm’s fascination with the images and imitatio of the Holy Family leads him to a ruined monastery. Here the novel’s protagonist notes the concordance of the family’s tableau vivant with one of the paintings that Joseph, who is the steward of the place, had himself created. Goethe’s narrative adapts a causal structure from the scientific usage of Lebenskraft to generate an aesthetic metaphor that transposes the work of the concept onto creative acts of reception:

Der Wirt merkte das Interesse seines Gastes und fing lächelnd an: Gewiß, Ihr bewundert die Übereinstimmung dieses Gebäudes mit seinen Bewohnern, die Ihr gestern kennenlerntet. Sie ist aber vielleicht noch sonderbarer, als man vermuten sollte: das Gebäude hat eigentlich die Bewohner gemacht. Denn wenn das Leblose lebendig ist, so kann es auch wohl Lebendiges hervorbringen.
O ja! versetzte Wilhelm: Es sollte mich wundern, wenn der Geist, der vor Jahrhunderten in dieser Bergöde so gewaltig wirkte und einen so mächtigen Körper von Gebäuden, Besitzungen und Rechten an sich zog und dafür mannigfaltige Bildung in der Gegend verbreitete, es sollte mich wundern, wenn er nicht auch aus diesen Trümmern noch seine Lebenskraft auf ein lebendiges Wesen ausübte. (FA 1.10:27)
His host noticed his interest and began with a smile, “Surely you are wondering at the correspondence between this building and its occupants, whom you encountered yesterday. But it is perhaps even more curious than one might expect: in actuality the building created its occupants. For if the inanimate is full of life, it can bring forth something alive.”
“Oh, yes,” Wilhelm replied, “it would surprise me to hear that the spirit that worked with such force in these desolate mountains hundreds of years ago and attracted itself to such a mighty body of buildings, estates, and privileges, from which the blessings of culture spread through the region—it would surprise me if it did not still exert a vital influence on living beings even from amidst these ruins. (van Heurck and Winston, 103)46

Joseph’s epigrammatic statement suggests the reciprocity between (creative) activity and the moribund, yet evocative substance of the ruined monastery, which has challenged him to revitalize and hold onto an imagined past. In Wilhelm’s reply, Lebenskraft and the monastery itself are imbued with agency and become transtemporal, or a matter of aesthetic reception that is nonetheless grounded in an awareness of historicity. As much as Lebenskraft here operates as a vital impulse, the question remains whether and how it can be realized.

The Metaphysics of Creation

The myth of Lucifer that closes the eighth book of Dichtung und Wahrheit (1811–1833; Poetry and Truth) returns to the metaphysical substrate of Lebenskraft in a cosmogonic narrative of Goethe’s metaphysical interests during his convalescence in Frankfurt between 1768 and 1769. The creation myth operates through a principle of polarity inherited from the Hermetic tradition and Neoplatonist emanationism: light and darkness and, most prominently, expansion and concentration.47Lebenskraft here refers to the activity of divine creation, which is dependent on a negative principle, Lucifer, who in opposition to the Holy Trinity appears as a fourth, heterogeneous element within the ceaseless creative work of Goethe’s pluralized divinity. Where Lebenskraft enters the mythic narrative is at the moment of creation, which witnessed the birth of a being (man), who was “qualified to restore the original connection with the deity”:

Sie [die Elohim] gaben dem unendlichen Sein die Fähigkeit, sich auszudehnen, sich gegen sie zu bewegen; der eigentliche Puls des Lebens war wieder hergestellt, und Lucifer selbst konnte sich dieser Einwirkung nicht entziehen. Dieses ist die Epoche, wo dasjenige hervortrat, was wir als Licht kennen, und wo dasjenige begann, was wir mit dem Worte Schöpfung zu bezeichnen pflegen. So sehr sich auch nun diese durch die immer fortwirkende Lebenskraft der Elohim stufenweise vermannigfaltigte; so fehlte es doch noch an einem Wesen, welches die ursprüngliche Verbindung mit der Gottheit wiederherzustellen geschickt wäre, und so wurde der Mensch hervorgebracht (FA 1.14:384)
They gave the infinite essence the capacity of expanding, of moving towards the deity. The real pulse of life was restored again, and Lucifer himself could not escape its influence. This is the epoch when the thing we know as light emerged, and when the process began that we customarily designate with the word “creation.” Although this by degrees became more multifarious, thanks to the ever-active life energy of the Elohim, what was still missing was a being qualified to restore the original connection with the deity; and so man was brought forth (Heitner, 262-63)48

The internal logic of Goethe’s creation myth can be elaborated in Aristotelian terms. Accordingly, Lucifer (whose names derives from the Latin word for light) provides the material substance out of which life can develop. For this reason, the phrase “der eigentliche Puls des Lebens war wiederhergestellt” (FA 1.14:384; The real pulse of life was restored again) is a linguistic misdirection. It implies a return or repetition, when the condition of possibility of life itself is contingent on Lucifer, whose negative concentration of matter is central to the process of creation. What is shared by these two literary examples of Lebenskraft is their suggestion of the persistence of a vital force. However ambiguous or loosely defined the term remained for Goethe within the nascent life sciences, and however frustrating he found it in his metacritical reflections, within his literary practice, at least, it could achieve aesthetic vitality.


Goethe’s primary engagement with Lebenskraft as a scientific concept paralleled the growth of its popularity in the debates of the 1790s, when his metacritical reflections produced skepticism about the term’s usefulness for science. Accordingly, even when it was absorbed into Goethe’s scientific writings, the lexeme Lebenskraft functioned primarily as a descriptive term rather than heuristic concept. But the conceptual fluidity of Lebenskraft also effectively contributed to its recuperation in Goethe’s literary practice as a figure of thought for the boundless, demiurgic activity of all generative processes, including the creative activity of the artist configured as second creator.

  1. See Lynn K. Nyhart, Biology Takes Form: Animal Morphology and the German Universities, 1800–1900 (Chicago: Chicago University Press, 1995), 37.
  2. Unless otherwise noted, works by Goethe are cited according to the Frankfurt edition (FA): Johann Wolfgang von Goethe, Sämtliche Werke, Briefe, Tagebücher und Gespräche, eds. Hendrik Birus, Dieter Borchmeyer, Karl Eibl, et. al., 40 vols. (Frankfurt a.M.: Deutscher Klassiker Verlag, 1987–2013), 1.25:770. Hereafter cited as FA in the body of the text.
  3. Joan Steigerwald, Experimenting at the Boundaries of Life. Organic Vitality in Germany around 1800 (Pittsburgh, PA: U of Pittsburgh P, 2019), 43.
  4. See, for example, James L. Larson, “Vital Forces: Regulative Principles or Constitutive Agents? A Strategy in German Physiology, 1786–1802,” Isis 70 no. 2 (June 1979): 235-49; Brigitte Lohff, “Die Entwicklung des Experimentes im Bereich der Nervenphysiologie: Gedanken und Arbeiten zum Begriff der Irritabilität und der Lebenskraft,” Sudhoffs Archiv 64 (1980): 105–29.
  5. Shirley A. Roe, Matter, Life, and Generation: Eighteenth-Century Embryology and the Haller-Wolff Debate (Cambridge: Cambridge UP, 1981), 106.
  6. See Ronald H. Brady, “Form and Cause in Goethe’s Morphology,” in Goethe and the Sciences: A Re-Appraisal, eds. Frederick Amrine, Francis J. Zucker, and Harvey Wheeler (Dordrecht: Reidel, 1987), 257–300.
  7. Frederick C. Beiser, German Idealism. The Struggle Against Subjectivism, 1781–1801 (Cambridge, MA: Harvard UP, 2002), 523–24.
  8. Jocelyn Holland has stressed the interactions between the scientific and poetic in Goethe: Jocelyn Holland, German Romanticism and Science. The Procreative Poetics of Goethe, Novalis, and Ritter (New York and London: Routledge, 2009). On the interactions between the scientific and the aesthetic, see Denise Gigante, Life: Organic Form and Romanticism (New Haven, CT: Yale UP, 2009).
  9. See Gabriel Trop, “Kraft,” Goethe-Lexicon of Philosophical Concepts 1 no. 1 (January 2021).
  10. John H. Zammito, The Gestation of German Biology. Philosophy and Physiology from Stahl to Schelling (Chicago: U of Chicago P, 2018), 245.
  11. Shirley A. Roe, “The Life Sciences,” in The Cambridge History of Science, eds. David C. Lindberg and Ronald L. Numbers, vol 4. Eighteenth-Century Science, ed. Roy Porter (Cambridge: Cambridge UP, 2003), 397–416.
  12. See Peter Hanns Reill, Vitalizing Nature in the Enlightenment (Berkeley, CA: U of California P, 2005), 7.
  13. Johann Friedrich Blumenbach, Über den Bildungstrieb und das Zeugungsgeschäfte (Göttingen: Dieterich, 1781), 12–13.
  14. See Jessica Riskin, The Restless Clock. A History of the Centuries-Long Argument of What Makes Living Things Tick (Chicago: U of Chicago P, 2016), 98.
  15. See Riskin, The Restless Clock.
  16. Sibille Mischer, Der verschlungene Zug der Seele: Natur, Organismus und Entwicklung bei Schelling, Steffens und Oken (Würzburg: Königshausen & Neumann, 1997), 83.
  17. Eve-Marie Engels, Die Teleologie des Lebendigen (Berlin: Duncker and Humblot, 1982), 102.
  18. Lebenskraft is given (under “Kraft”), for example, as the translation of vis vitalis in Christoph Ernst Steinbach, Vollständiges Deutsches Wörter-Buch (Breslau: Korn, 1734), 923.
  19. See Jennifer Wynne Hellwarth, “Pneuma – Sexuality – Sex Difference: From Arabic to European Philosophy and Medical Practice,” in The Early History of Embodied Cognition 1740–1920. The Lebenskraft-Debate and Radical Reality in German Science, Music, and Literature, eds. John A. McCarthy, Stephanie M. Hilger, Heather L. Sullivan, et. al. (Leiden and Boston: Brill, Rodopi, 2016), 53–74.
  20. See Alice Kuzniar, The Birth of Homeopathy out of the Spirit of Romanticism (Toronto: U of Toronto P, 2017), 117.
  21. Andrea Gambarotto, Vital Forces, Teleology and Organization. Philosophy of Nature and the Rise of Biology in Germany (Cham: Springer, 2018), 35.
  22. Steigerwald, Experimenting at the Boundaries of Life, 42.
  23. Zammito, The Gestation of German Biology, 294–95.
  24. Timothy Lenoir, The Strategy of Life: Teleology and Mechanics in Nineteenth-Century German Biology (Chicago: U of Chicago P, 1982), 45. Goethe wrote to Herder in 1793 or 1794 approvingly of Kielmeyer’s lecture (WA 4.10:132).
  25. John A. McCarthy, “Energy and Schiller’s Aesthetics from the ‘Philosophical’ to the Aesthetic Letters,” in Who Is This Schiller Now? Essays on his Reception and Significance, ed. Jeffrey L. High, Nicholas Martin and Norbert Oellers (Rochester, NY: Camden House, 2011), 165–86.
  26. Johann Wolfgang von Goethe. Die Schriften zur Naturwissenschaft, ed. Dorothea Kuhn (Weimar: Hermann Böhlaus Nachfolger, 1986), 2.9A:411–12. Hereafter cited as LA in the body of the text.
  27. See Robert J. Richards, “Did Goethe and Schelling Endorse Species Evolution?,” in Marking Time. Romanticism and Evolution, ed. Joel Faflak (Toronto: U of Toronto P, 2017), 219–38.
  28. This theory was hotly debated in the eighteenth century, with Buffon and John Needham advancing vitalist theories of spontaneous generation based on experiments with infusoria and Lazzaro Spallanzani repudiating them. See John Farley, “The Spontaneous Generation Controversy (1700–1860): The Origin of Parasitic Worms,” Journal of the History of Biology 5 no. 1 (Spring 1972): 95–125.
  29. Roland Borgards, “Proteus. Liminal Zoologie bei Goethe und Büchner,” in Liminale Anthropologien. Zwischenzeiten, Schwellenphänomene, Zwischenräume in Literatur und Philosophie, eds. Jochen Achilles, Roland Borgards and Brigitte Burrichter (Würzburg: Königshausen & Neumann, 2012), 131–44.
  30. Johann Wolfgang von Goethe, Scientific Studies, ed. and trans. Douglas Miller (Princeton, NJ: Princeton UP, 1995), 59. Hereafter cited as Miller in the body of the text for quotations. Translation revised by JR.
  31. Maike Arz, Literatur und Lebenskraft. Vitalistische Naturforschung und bürgerliche Literatur um 1800 (Stuttgart: M und P, Verlag für Wissenschaft und Forschung, 1996), 27.
  32. For an overview of Humboldt’s development away from Lebenskraft, see Thomas Schmuck, “Von der Lebenskraft zur Theorie des Lebens,” in Alexander von Humboldt-Handbuch: Leben – Werk – Wirkung, ed. Ottmar Ette (Metzler: Stuttgart, 2018), 144–46.
  33. Alexander von Humboldt, Aphorismen aus der chemischen Physiologie der Pflanzen, trans. Gotthelf Fischer (Leipzig: Voss und Compagnie, 1794), 9.
  34. Alexander von Humboldt, Sämtliche Schriften, ed. Oliver Lubrich and Thomas Nehrlich, 10 vols. (Munich: Deutscher Taschenbuch Verlag, 2019), 1:153.
  35. Alexander von Humboldt, Views of Nature, ed. by Stephen T. Jackson and Laura Dassow Walls, trans. Mark W. Person (Chicago: U of Chicago P, 2014), 264. Hereafter cited as Person in the body of the text.
  36. Andreas W. Daum, “Social Relations, Shared Practices, and Emotions: Alexander von Humboldt’s Excursion into Literary Classicism and the Challenges to Science around 1800,” The Journal of Modern History 91 no. 1 (March 2019): 1–37.
  37. Humboldt, Sämtliche Schriften, I:153.
  38. For a discussion of the importance of social sympathies and notions of continued existence, see Lieselotte E. Kurth-Voigt, Continued Existence, Reincarnation, and the Power of Sympathy in Classical Weimar (Rochester, NY: Camden House, 1999).
  39. See Dorothea von Mücke, “Goethe’s Metamorphosis: Changing Forms in Nature, the Life Sciences, and Authorship,” Representations 95 no. 1 (Summer 2006): 27–52.
  40. See David Wellbery, “Form,” Goethe-Lexicon of Philosophical Concepts 1 no. 1 (January 2021).
  41. As Peter Hanns Reill has argued: Peter Hanns Reill, “Bildung, Urtyp and Polarity: Goethe and Eighteenth-Century Physiology,” Goethe Yearbook 3 (1986): 139–48.
  42. As Gabriel Trop has noted: “Kraft,” Goethe-Lexicon of Philosophical Concepts.
  43. I am indebted to Amanda Jo Goldstein’s reading of this passage: Amanda Jo Goldstein, Sweet Science. Romantic Materialism and the New Logics of Life (Chicago: U of Chicago P, 2017), 79–81.
  44. Eckart Förster, “Goethe and the ‘Auge des Geistes’,” Deutsche Vierteljahrsschrift für Literaturwissenschaft und Geistesgeschichte 75 (2001): 87–101.
  45. Astria Orle Tantillo, The Will to Create: Goethe’s Philosophy of Nature (Pittsburgh, PA: U of Pittsburgh P, 2002), x.
  46. Johann Wolfgang von Goethe, Conversations with German RefugeesWilhelm Meister’s Journeyman Years, ed. Jane K. Brown, trans. Jan van Heurck and Krishna Winston (Princeton, NJ: Princeton UP, 1994), 103.
  47. Rolf Christian Zimmermann, Das Weltbild des jungen Goethe. Studien zur hermetischen Tradition des deutschen 18. Jahrhunderts, 2 vols (Munich: Fink, 1969–79).
  48. Johann Wolfgang von Goethe, From My Life: Poetry and Truth, pts. 1-3, ed. by Thomas P. Saine, Jeffrey L. Sammons, trans. Robert R. Heitner (Princeton, NJ: Princeton UP, 1994), 262–63.

Related Entries in the GLPC

  • EntelechieEntelechy
  • FormForm
  • GestaltShape
  • KraftForce
  • LebenLife
  • MaterieMatter
  • MetamorphoseMetamorphosis
  • MorphologieMorphology
  • Nature, NatürlichNature, Natural
  • OrganismusOrganism
  • Polarit&amul;t und SteigerungPolarity and Intensification
  • Productivit&amul;tProductivity
  • TriebDrive
  • TypusType
  • Zarte EmpirieDelicate empiricism

Works Cited and Further Reading

  • Arz, Maike. Literatur und Lebenskraft. Vitalistische Naturforschung und bürgerliche Literatur um 1800. Stuttgart: M und P, Verlag für Wissenschaft und Forschung, 1996.
  • Beiser, Frederick C. German Idealism. The Struggle Against Subjectivism, 1781–1801. Cambridge, MA: Harvard UP, 2002.
  • Bell, Matthew. Goethe’s Naturalist Anthropology: Man and Other Plants. Oxford: Clarendon P, 1994.
  • Blumenbach, Johann Friedrich. Über den Bildungstrieb und das Zeugungsgeschäfte. Göttingen: Dieterich, 1781.
  • Borgards, Roland. “Proteus. Liminal Zoologie bei Goethe und Büchner.” In Liminale Anthropologien. Zwischenzeiten, Schwellenphänomene, Zwischenräume in Literatur und Philosophie, edited by Jochen Achilles, Roland Borgards and Brigitte Burrichter, 131–44. Würzburg: Königshausen & Neumann, 2012.
  • Brady, Ronald H. “Form and Cause in Goethe’s Morphology.” In Goethe and the Sciences: A Re-Appraisal. Edited by Frederick Amrine, Francis J. Zucker and Harvey Wheeler, 257-300. Dordrecht: Reidel, 1987.
  • Daum, Andreas W. “Social Relations, Shared Practices, and Emotions: Alexander von Humboldt’s Excursion into Literary Classicism and the Challenges to Science around 1800.” The Journal of Modern History 91 no. 1 (March 2019): 1–37.
  • Engels, Eve-Marie. Die Teleologie des Lebendigen. Berlin: Duncker and Humblot, 1982.
  • Farley, John. “The Spontaneous Generation Controversy (1700-1860): The Origin of Parasitic Worms.” Journal of the History of Biology 5 no. 1 (Spring 1972): 95–125.
  • Förster, Eckart. “Goethe and the ‘Auge des Geistes’.” Deutsche Vierteljahrsschrift für Literaturwissenschaft und Geistesgeschichte 75 (2001): 87–101.
  • Gambarotto, Andrea. Vital Forces, Teleology and Organization. Philosophy of Nature and the Rise of Biology in Germany. Cham: Springer, 2018.
  • Gigante, Denise. Life: Organic Form and Romanticism. New Haven, CT: Yale UP, 2009.
  • Goethe, Johann Wolfgang von. Goethes Werke. Im Auftrag der Großherzogin Sophie von Sachsen. 143 vols. Weimar: Hermann Böhlau, 1887–1919.
  • ———. Die Schriften zur Naturwissenschaft (LA). Edited by Dorothea Kuhn. Weimar: Hermann Böhlaus Nachfolger, 1986.
  • ———. Sämtliche Werke, Briefe, Tagebücher und Gespräche. Edited by Hendrik Birus, Dieter Borchmeyer, Karl Eibl, et. al. 40 vols. Frankfurt a.M.: Deutscher Klassiker Verlag, 1987–2013.
  • ———. Conversations of German Refugees—Wilhelm Meister’s Journeyman Years or The Renunciants. Edited by Jane K. Brown. Translated by Jan van Heurck and Krishna Winston. Princeton, NJ: Princeton UP, 1994.
  • ———, From My Life: Poetry and Truth, pts. 1–3. Edited by Thomas P. Saine, Jeffrey L. Sammons. Translated by Robert R. Heitner. Princeton, NJ: Princeton UP, 1994.
  • ———. Scientific Studies. Edited and translated by Douglas Miller. Princeton, NJ: Princeton UP, 1995.
  • Goldstein, Amanda Jo. Sweet Science. Romantic Materialism and the New Logics of Life. Chicago: U of Chicago P, 2017.
  • Gottdenker, Paula. “Three Clerics in Pursuit of ‘Little Animals’.” Clio Medica 14 no. 3/4 (1980): 213–24.
  • Hellwarth, Jennifer Wynne, “Pneuma – Sexuality – Sex Difference: From Arabic to European Philosophy and Medical Practice.” In The Early History of Embodied Cognition 1740-1920. The Lebenskraft-Debate and Radical Reality in German Science, Music, and Literature. Edited by John A. McCarthy, Stephanie M. Hilger, Heather L. Sullivan, et. al., 53–74. Leiden and Boston: Brill, Rodopi, 2016.
  • Holland, Jocelyn. German Romanticism and Science. The Procreative Poetics of Goethe, Novalis, and Ritter. New York and London: Routledge, 2009.
  • Humboldt, Alexander von. Aphorismen aus der chemischen Physiologie der Pflanzen. Translated by Gotthelf Fischer. Leipzig: Voss und Compagnie, 1794.
  • ———. Views of Nature. Edited by Stephen T. Jackson and Laura Dassow Walls. Translated by Mark W. Person. Chicago: U of Chicago P, 2014.
  • ———. Sämtliche Schriften. Edited by Oliver Lubrich and Thomas Nehrlich. 10 vols. Munich: Deutscher Taschenbuch Verlag, 2019.
  • Kurth-Voigt, Lieselotte E. Continued Existence, Reincarnation, and the Power of Sympathy in Classical Weimar. Rochester, NY: Camden House, 1999.
  • Kuzniar, Alice. The Birth of Homeopathy out of the Spirit of Romanticism. Toronto: U of Toronto P, 2017.
  • Larson, James L. “Vital Forces: Regulative Principles or Constitutive Agents? A Strategy in German Physiology, 1786-1802.” Isis 70 no. 2 (June 1979): 235–49.
  • Lenoir, Timothy. The Strategy of Life: Teleology and Mechanics in Nineteenth-Century German Biology. Chicago: U of Chicago P, 1982.
  • Lohff, Brigitte. “Die Entwicklung des Experimentes im Bereich der Nervenphysiologie: Gedanken und Arbeiten zum Begriff der Irritabilität und der Lebenskraft.” Sudhoffs Archiv 64 (1980): 105–29.
  • McCarthy, John A. “Energy and Schiller’s Aesthetics from the ‘Philosophical’ to the Aesthetic Letters.” In Who Is This Schiller Now? Essays on his Reception and Significance. Edited by Jeffrey L. High, Nicholas Martin and Norbert Oellers, 165–86. Rochester, NY: Camden House, 2011.
  • Mischer, Sibille. Der verschlungene Zug der Seele: Natur, Organismus und Entwicklung bei Schelling, Steffens und Oken. Würzburg: Königshausen & Neumann, 1997.
  • Mücke, Dorothea von. “Goethe’s Metamorphosis: Changing Forms in Nature, the Life Sciences, and Authorship.” Representations 95 no. 1 (Summer 2006): 27–52.
  • Nyhart, Lynn K. Biology Takes Form: Animal Morphology and the German Universities, 1800–1900. Chicago: U of Chicago P, 1995.
  • Reill, Peter Hanns. “Bildung, Urtyp and Polarity: Goethe and Eighteenth-Century Physiology.” Goethe Yearbook 3 (1986): 139–48.
  • ———. Vitalizing Nature in the Enlightenment. Berkeley, CA: U of California P, 2005.
  • Richards, Robert J. “Did Goethe and Schelling Endorse Species Evolution?” In Marking Time. Romanticism and Evolution. Edited by Joel Faflak, 219–38. Toronto: U of Toronto P, 2017.
  • Riskin, Jessica. The Restless Clock. A History of the Centuries-Long Argument of What Makes Living Things Tick. Chicago: U of Chicago P, 2016.
  • Roe, Shirley A. Matter, Life, and Generation: Eighteenth-Century Embryology and the Haller-Wolff Debate. Cambridge: Cambridge UP, 1981.
  • ———. “The Life Sciences.” In The Cambridge History of Science. Edited by David C. Lindberg and Ronald L. Numbers. 8 vols. Vol. 4, Eighteenth-Century Science, edited by Roy Porter, 397–416. Cambridge: Cambridge UP, 2003.
  • Schmuck, Thomas. “Von der Lebenskraft zur Theorie des Lebens.” In Alexander von Humboldt-Handbuch: Leben – Werk – Wirkung. Edited by Ottmar Ette, 144-46. Metzler: Stuttgart, 2018.
  • Steigerwald, Joan. Experimenting at the Boundaries of Life. Organic Vitality in Germany around 1800. Pittsburgh, PA: U of Pittsburgh P, 2019.
  • Steinbach, Christoph Ernst. Vollständiges Deutsches Wörter-Buch. Breslau: Korn, 1734.
  • Tantillo, Astrida Orle. The Will to Create: Goethe’s Philosophy of Nature. Pittsburgh, PA: U of Pittsburgh P, 2002.
  • Trop, Gabriel. “Kraft.” Goethe-Lexicon of Philosophical Concepts 1 (January 2021).
  • Wellbery, David. “Form.” Goethe-Lexicon of Philosophical Concepts 1 (January 2021).
  • Zammito, John H. The Gestation of German Biology. Philosophy and Physiology from Stahl to Schelling. Chicago: U of Chicago P, 2018.
  • Zimmermann, Rolf Christian. Das Weltbild des jungen Goethe. Studien zur hermetischen Tradition des deutschen 18. Jahrhunderts. 2 vols. Munich: Fink, 1969–79.