1. Zeller and Fischer

Eduard Zeller is best known today for his Outlines of the History of Greek Philosophy,¹ a compendium which is still widely used as a quick introduction to classical philosophy. If it were not for the stiffness and awkwardness of the English prose, which belie a translation from German, one might assume the author was a penurious classics scholar eager to make a few bob from the sale of a potboiler. But Zeller was no ordinary scholar. He was not only an eminent 19th century philosophical historian but also a central figure in the revival of neo-Kantianism. No study of neo-Kantianism can afford to ignore him.

Zeller and Fischer were in many respects perfect counterparts. They were two of the greatest philosophical historians of their age. What Fischer was to modern philosophy, Zeller was to ancient. Just as, for generations, the standard work on the history of modern philosophy was Fischer’s Geschichte der modernen Philosophie, so, even today, the standard work on the history of classical philosophy is Zeller’s Philosophie der Griechen.² It could not have hindered the rise of Kant’s stature in Germany that, from complementary historical perspectives, the two most eminent philosophical historians declared their allegiance to Kant. Whether seen from a classical or modern viewpoint, Kant seemed to be the saviour of German philosophy.

Though near contemporaries of equal stature, Zeller and Fischer met only late in their careers, and then only occasionally.³ When Zeller went to Berlin in 1872, Fischer (p.256) became his successor in Heidelberg. For a while the two men were rivals for the post in Heidelberg, which Zeller eventually received only because Fischer turned it down.⁴ Laden with honours and memories of glorious careers, the two men lived in retirement in Stuttgart, where Zeller would sometimes visit Fischer. Zeller, who lived to be a sprightly ninety-four, went to see Fischer in August 1905, only to be turned away from the door.⁵ He was crushed to learn that Fischer, who was ten years younger, was so unwell and senescent that he could not receive guests.

For the revival of Kant in the 1860s, Zeller was of no less importance than Fischer. In the early 1860s both gave influential lectures calling for a return to Kant. Though there is no evidence of collaboration, their neo-Kantian programmes show remarkable parallels. Both contend that only Kant can solve the identity crisis of philosophy and save it from imminent obsolescence. Both argue that philosophy should be re-conceived as epistemology if it is to have its own place in the modern division of the sciences. And both see Kant’s philosophy as the middle path between the rosy fantasies of speculative idealism and the grim realities of materialism. Their neo-Kantian paths would diverge only over one central issue: Zeller supported Trendelenburg in his famous dispute with Fischer.⁶

Not the least respect in which Zeller and Fischer are counterparts concerns their early backgrounds. Both were Hegelians in their early careers. Both wrote for Arnold Ruge’s Jahrbücher; both were close friends of David Friedrich Strauß, who had a decisive influence in shaping their early theological views; and both shared a common fate in suffering persecution for their left-Hegelian pantheism. The stories behind their conversions to Kant are, however, very different. While Fischer, as we have seen, never became a complete convert and never fully renounced his Hegelianism, Zeller became a total disciple and abandoned his Hegelianism entirely.

The story of Zeller’s conversion to Kant is of great interest to us as students of the history of neo-Kantianism. Why, exactly, did Zeller abandon Hegel? And why did he convert to Kant? Given Zeller’s importance for neo-Kantianism, the answers to these questions should shed some light on the origins of the movement. Yet it is precisely here that the historical record proves to be very obscure. Nowhere in his published correspondence or in his writings does Zeller himself offer an explanation. We have to reconstruct the history from the few clues available to us. A large part of our task in this chapter will be to retrace Zeller’s intellectual development and to show how he was led away from Hegel and towards Kant. We will then examine Zeller’s major writings on Kant.

(p.257) 2. Early Tübingen Years

Eduard Zeller, the eighth of nine children, was born January 22, 1814, in the village of Kleinbottwar in Swabia.⁷ Though descending from a long line of Protestant clergy, his father, Johann Heinrich Zeller, was a minor civil servant in Kleinbottwar. At a very early age Zeller learned classical languages, and already at eight showed a proficiency in ancient Greek, a talent which would serve him well for his later work on classical philosophy. When still very young Zeller decided, in accord with family tradition, to study theology for a career in the church. And so, in October 1827, after finishing primary school, he went straight to the evangelical seminary at Maulbronn. It was during his Maulbronn years that he first met a figure who would later play a fateful role in his life: David Friedrich Strauß (1808–1874).⁸ A temporary teacher at the seminary, Strauß recognized Zeller’s precocious talents, little knowing then how fate would later intertwine him with his student.

In autumn 1831 Zeller went to the Tübinger Stift, the fabled Protestant seminary, where, nearly half a century earlier, Schelling, Hegel and Hölderlin had been students. There Zeller was the student of Ferdinand Baur (1792–1860), who had joined the Stift in 1826.⁹ Baur was the father of the Tübingen critical school of theology, whose aim was to apply the new historical methods to the study of early Christianity and the Bible. An imposing yet beloved teacher, Baur soon became the decisive figure in Zeller’s intellectual development. According to Dilthey, “the ideal of Zeller’s life” was “to appropriate, support and continue [Baur’s] researches.”¹⁰ The closeness of Zeller to Baur was such that, in 1847, he married Baur’s daughter.

For his four years of study at the Stift, Zeller had to study philosophy for the first three semesters. In his first semester he read Plato’s Republic and Kant’s Kritik der reinen Vernunft, chosing as his first essay topic Kant’s distinction between phenomena and noumena.¹¹ Already in these semesters Zeller had acquired a thorough grounding in classical German philosophy, reading the major writings of Kant, Fichte, Schelling, Jacobi and Hegel.¹² Another early essay, written in the Summer (p.258) Semester of 1832, was on the development of transcendental idealism after Kant, which, according to his tutor, “left nothing to be desired” for its historical accuracy and philosophical insight.¹³ Zeller says that in those early days he had not heard the name Schopenhauer, and that he knew about but had little interest in Herbart.¹⁴

Zeller’s main philosophy teacher at the Stift was the very man who once briefly taught him at the Maulbronn seminary: David Friedrich Strauß. In May 1832, Strauß, a graduate at the Stift, had become an instructor there. He had just spent the winter of 1831–32 in Berlin, where he had attended Hegel’s last lectures. Strauß introduced Zeller not only to Plato and Schleiermacher but also to Hegel, who was then hardly known at his alma mater. A self-confessed Hegelian, Strauß took extra pains to explain the intricacies of Hegel’s system in plain and simple language to his young students. A close friendship developed between Strauß and Zeller, a bond strong enough to last for the rest of their lives. Though Zeller was intellectually and personally closer to Baur,¹⁵ he would support Strauß throughout all the dramas and struggles of his later career. He eventually became Strauß’s biographer and the editor of his correspondence.¹⁶

After the completion of his studies in 1836, Zeller, following a Stift tradition, received a stipend for a Wanderjahr. Following in Strauß’s footsteps, he decided to make a pilgrimage to Berlin, then the centre of theological and philosophical studies in Germany. Though Hegel and Schleiermacher were now dead, Zeller thought that he could at least learn from Hegel’s disciples. So, well supplied with introductions from Strauß, he duly met the leaders of the Hegelian school: Karl Michelet (1801–1893), Phillip Marheineke (1780–1846), Eduard Gans (1797–1839) and Leopold Henning (1791–1806). He also met an old friend of Strauβ, Wilhelm Vatke (1806–82), who managed to arrange for him a tea with Hegel’s widow.

In the summer of 1837 Zeller returned to his Swabian homeland, where he began his clerical career by preaching in rural districts. But the lure of academic life proved too great for him. By 1839 he had returned to his alma mater, first as a Repetent (i.e. a tutor) and then in 1840 as a Privatdozent. The early years as a Dozent in Tübingen were Zeller’s halcyon days. It was during these years that he formed a close intellectual circle with other Baur students—Christian Märklin (1807–1849), Friedrich Vischer (1807–1887), Albert Schwegler (1819–1857), Gottlieb Planck (1819–1880), and Ernst Rapp (1806–1879)—to discuss philosophy, theology and politics. This circle shared common philosophical, theological and political views, which could be loosely described as moderate to left of centre Hegelianism.¹⁷ Together, they created (p.259) two journals to serve as mouthpieces for their views, the Jahrbücher der Gegenwart,¹⁸ which was edited by Schwegler, and the Theologische Jahrbücher,¹⁹ which was edited by Zeller himself.

That the young Zeller was something of a Hegelian there cannot be any doubt.²⁰ He was a frequent contributor to Arnold Ruge’s Hallische Jahrbücher, a Young Hegelian journal begun in 1837 but supressed in 1841, and to Schwegler’s Jahrbücher der Gegenwart, a more moderate replacement for Ruge’s journal.²¹ Zeller’s allegiance to Hegel is made plain from a letter Strauss wrote to him in February 1844, praising Zeller for his respectful attitude towards “our old master” and for not treating him, like so many upstart youths, “like a dead dog”.²² “Our old master” meant, of course, Hegel. Strauss was referring to Zeller’s recent treatment of Hegel in his Philosophie der Griechen, where he defended Hegel’s history of philosophy against Fries’ objections.²³

Yet the question remains: How much of a Hegelian was the young Zeller? Unlike Fischer, he was never a died-in-the-wool disciple, and already by the mid-1840s he had developed a critical distance towards Hegel. In his Philosophie der Griechen, the very text Strauβ praises for having a respectful attitude towards their “old master”, Zeller is careful to expound a method that is not strictly Hegelian, and that is indeed partially anti-Hegelian. He recommends a method that combines the speculative with the historical, and he is very wary of the dangers of an entirely speculative method: the invention of arbitrary constructions, the imposition of a priori schemata on the subject matter. While Zeller approves the Hegelian practice of tracing “the organic development of thought”, “the connection of the systems”, he does not think that this should come from above but only from below, from dwelling in the particularities of the facts of history (v, 7–8). In suggesting these criticisms of Hegel, Zeller was endorsing the common complaints made against his methodology by the historical school. It is also noteworthy that though Zeller advises the philosophical historian to determine “the organic development of thought”, he does not identify this concern with Hegel alone. While Hegel was its most conspicuous protagonist, Zeller finds the same concern in the work of Schleiermacher, Ritter and Hermann (2).

(p.260) The programme behind Zeller’s Theologische Jahrbücher was also far from a strictly Hegelian enterprise. In his early 1846 article ‘Die Theologie der Gegenwart’,²⁴ his account of all the theological schools of his day, Zeller does take a stand on behalf of what he calls “speculative theology”, which was the usual term for the Hegelian version of the discipline. But it soon becomes clear that he does not mean anything particularly Hegelian by this phrase. He defines “speculative theology” as the attempt to explain religion from the universal essence of mind, which could hardly be described as a unique or characteristic Hegelian enterprise (19). Although Zeller praises Hegel’s philosophy for providing the most up-to-date form of such theology, and even for having taken it a step further than Schleiermacher, he does not identify speculative theology with Hegel alone. He says that the same enterprise was carried on by Schleiermacher;²⁵ and he even imagines a progression beyond Hegel that might realize more fully the ideal of a speculative theology (20). What form that progression might take he does not explain.

That Zeller was already taking decisive steps away from Hegel in the mid-1840s is fully apparent from some other articles in his Theologische Jahrbücher. In an article on the nature of religion,²⁶ Zeller shows himself to be highly critical of Hegel’s philosophy of religion, which he finds much too intellectualistic. By identifying religion with a stage of consciousness, the representation of the infinite, Hegel came close to reducing it down to a mental attitude, neglecting its practical side in ritual and moral conduct (55–64). And in an article on freedom of will,²⁷ Zeller, in self-conscious opposition to Hegel’s and Schleiermacher’s determinism, defends the concept of freedom as the power to choose, the ability to decide and act otherwise. Such freedom requires the possibility of contingency, a possibility that Hegel denies (394, 444). For Hegel, contingency is possible only from the standpoint of reflection, which cannot know entirely all the causes behind an event (393). Significantly, in defending freedom in this sense, Zeller had already broke decidedly with the monism and determinism of Hegel’s pantheistic worldview.

Yet, despite his growing distance from Hegel, the young Zeller was no closer to Kant. He was just as critical of Kant’s philosophy of religion, which committed the opposite error of Hegel’s: in reducing religion down to morals, Kant saw its practical but not its intellectual side.²⁸ Although Zeller’s position on freedom would seem to bring him closer to Kant, who had famously defended freedom of choice, Zeller explicitly rejects Kant’s theory of freedom (433, 437–438).²⁹ Zeller does not think that (p.261) we can harmonize moral choice with natural necessity, as Kant had, and he attempts to make them compatible by arguing that the general laws of nature are valid only en masse but not in all particular cases (398, 439). So, for Zeller, unlike Fischer, affirming freedom of choice was no reason to return to Kant.

Zeller’s distance from Kant in the 1840s leaves us with the question of why he became a Kantian at all. Obviously, we still have a lot of explaining to do. The answer lies with another crucial aspect of Zeller’s early intellectual career, one which we must now examine in detail: his project of historical criticism. It was only through the thorny thickets of historical criticism that the young Zeller would discover the path towards Königsberg.

3. Historical Criticism

The core of Zeller’s intellectual life during his later Tübingen years (1844–1847) revolved around Baur’s project of historical criticism. The circle that formed around Baur later became known as the “Tübingen historical school”, or more simply as “the Tübingen school” or “the critical school”. Zeller played a pivotal role in its organization and development as the founder and chief editor of its common journal, the Theologische Jahrbücher.³⁰ Since this project was so crucial to Zeller’s intellectual development, we need to examine it in a little detail.

Fortunately, the best account of the Tübingen school, at least for our purposes, is that provided by Zeller himself, who wrote a long retrospective article about it in 1859 for the Historische Zeitschrift.³¹ What was fundamental to, and characteristic of, the Tübingen school, Zeller informs us, was its methodology, its manner of treating sacred texts strictly as historical documents, that is, as writings produced by human beings under particular social, historical and cultural circumstances (268). This meant laying aside the traditional orthodox assumption that the Bible was the product of supernatural inspiration, as if everything it said had divine authority. The method of the Tübingen school, as Zeller describes it, was that of historical criticism, pure and simple. Such criticism consists in the rigorous examination of the evidence behind historical texts to determine their authorship and accuracy, so that we accept or reject what a text states about the past strictly according to the degree of evidence for or against it. The origins of this methodology lay with the new critical history (p.262) formed in the early 1800s by Barthold Niebuhr (1776–1831) and Leopold Ranke (1795–1886). Niebuhr had applied the method to Roman history in his Römische Geschichte (1811–1812), and Ranke had done the same to early modern history in his Geschichte der germanischen und romanischen Völker (1824). The programme of the Tübingen school was simply to extend that method to sacred history. This was indeed just how Zeller himself viewed the origins of the historical school when he wrote in the final sentence of his article: “Its ruling principles are only the same as those that have governed all German historical writing outside theology since Niebuhr and Ranke” (353).

Zeller stresses two additional features of historical criticism. First, it is meant to be entirely “free” or “radical”, that is, it lays aside all theological presuppositions or ecclesiastical guidelines, and it takes its method to its ultimate conclusions, whatever the consequences for church and dogma. Hence, in the forward to the Theologische Jahrbücher, Zeller vows to devote his journal to the ideals of “free enquiry”, “the freedom and consistency of thought” independent of all confessional loyalties.³² This means, as he later put it, that dogma should follow critique, not critique dogma (268). Second, historical critique is intended to be “scientific”. This means that it adopts the general scientific view of the world, that is, it accepts the universal validity of the laws of nature discovered by the empirical sciences. It assumes that natural laws hold without exception, that the laws true for the universe now were also so in the past, so that testimony about the extraordinary and abnormal has little or no probability. Such a method, when applied rigorously to the Bible, immediately renders suspect its entire supernatural dimension, all its prophecies and miracles. Perfectly aware of this consequence, Zeller himself insisted on this naturalism, which he saw as integral to the scientific status of criticism; he indeed admitted that there could be no compromise between it and the supernaturalism of the Bible: “Belief in miracles and critique are two things that exclude one another” (299).³³

Zeller was eager to distinguish historical criticism from two older forms of Biblical interpretation. Following his account, the Tübingen programme differs from not only Protestant orthodoxy, which saw the Bible as a divinely inspired document, but also from the old rationalism of the Enlightenment, which read the Bible as if its content were entirely rational and written by philosophers. The theologians of the Enlightenment had attempted to tone down the supernatural dimension of the Bible by interpreting its language about inspiration, miracles and prophecies in terms of symbols for moral and metaphysical truths, viz., the snake speaking to Eve, or the devil appearing to Jesus, were parables about inner spiritual conflicts. The chief problem with this rationalism, Zeller maintains, is that it was not sufficiently historical or critical. Although it had questioned whether the events narrated in the Bible are supernatural, it never doubted that these events occurred (273). Rather than (p.263) interpreting texts in their historical context and trying to understand them in the authors’ terms, the rationalists imposed their own constructions on the text, giving them a metaphysical or moral meaning never intended by their authors. It had assumed that the authors of the Bible were like modern Aufklärer or free-thinkers who were writing parables for the people in poetic and ornate language; once placed in their historical context, however, it becomes clear that these authors actually believed their prophecies and miracles.

Zeller also distinguishes the Tübingen school from two trends of contemporary theology: a tepid rationalism, which dares not take its criticism far enough, and a mellow orthodoxy, which softens its belief in the supernatural by making piecemeal concessions to rationalism (274).³⁴ Thus a theology of “timid compromise” has become the order of the day, Zeller complains. He insists that neither Schleiermacher nor Hegel have done much to change this sad state of affairs. Neither were sufficiently critical or historical because they never really challenged the sacred texts. Thus Schleiermacher’s dogmatics began with the assumption of “the basic mystery of Christ”, while the Hegelians simply accepted the claims to revelation in the Bible because their only interest was casting them in terms of the speculative concept (274–275).³⁵ In foisting all kinds of dialectical constructions on the text, the Hegelians proved themselves no better than their rationalist forbears.

For Zeller, the culmination of the historical criticism of the Tübingen school came with David Friedrich Strauβ’s Das Leben Jesu.³⁶ Taking the programme of radical criticism to its ultimate limits, Strauβ came to the conclusion that all the narratives in the Bible are false if they are taken as straightforward accounts of supernatural events. Strauβ found inconsistencies in the testimony of the four gospels; and he was rigorous in applying the standards of ordinary induction to the texts, coming to the unsurprising conclusion that it was improbable that any miracles ever occurred. Strauβ denied, however, that these stories were the product of self-conscious deception on the part of a conspiracy of priests—the old account of the free-thinkers—and instead explained them as myths. Myth was the central theme of Strauβ’s book, the concept he invoked to replace the reason of the rationalists and the inspiration of the orthodox. According to Zeller, Strauβ made three central claims about myth: 1) it is poetry, not history; 2) it is the work not of an individual alone but of an entire community; and 3) it is not a legend created by the imagination but a story serving practical and dogmatic interests (278). In short, myths are “Christian folktales” (Volkssage), though folktales created for religious interests (278). The interests of the early Christians were (p.264) twofold: to glorify Christ; and to demonstrate that the Judaic prophecies about the messiah had been fulfilled.

Although he saw Strauβ’s book as the epitome of the Tübingen school, Zeller himself was far from endorsing it entirely. Like Baur, he felt that the book was much too negative and much too polemical. After demolishing all the narratives of the Bible, Strauβ had made no effort to construct a more truthful history (279–282). Zeller was also critical of the Hegelian assumptions behind Strauβ’s concept of religion, which understood religion in a much too theoretical manner.³⁷ Strauβ wrote as if the ancient prophets and apostles were want-to-be Hegelian philosophers! Still, despite these reservations, Zeller stood by the negative teachings of Strauβ’s book, which he regarded as indisputable and epochal. Although one could quarrel with Strauβ on particular points, one could not contest his general scepticism about the old Protestant dogma of the literal truth of the Bible (277–278). Thanks largely to Strauβ, Zeller came to the conclusion that the entire worldview of the Christian church—its concept of revelation, its principle that salvation came with faith alone—could no longer be accepted in the modern age.³⁸ Although Zeller was worried about “the nihilism” of a completely negative critique, and although he demanded nothing less than “a complete reconstruction” of theology, he made few positive suggestions about how to avoid this nihilism or what this new theology should be. One thing alone was entirely clear to him: that after Strauβ there could be no going back to the past.

Seen from a broader historical perspective, the historical criticism of the Tübingen school was the result of three powerful historical influences. One was the historical criticism of Niebuhr and Ranke, as we have already seen. Another influence was Spinoza, whose naturalist biblical criticism was the precedent for Strauβ. Last but not least, there was Kant. While Zeller never mentions Spinoza, probably because he still remained so controversial, he does not hesitate to acknowledge, on two different occasions, his debts to the sage of Königsberg. At the close of ‘Die Theologie der Gegenwart’ Zeller states expressly that the standpoint of criticism of the historical school grew out of the Kantian Copernican Revolution (27); and in the beginning of his article ‘Ueber das Wesen der Religion’ he claims that only since Kant based philosophy on human self-consciousness has it been possible to explain the place of religion in the general economy of mental life (28). In stressing the importance of Kant for the Tübingen school, Zeller was inter alia alluding to Kant’s Transcendental Dialectic. The disposition to hypostasize concepts, which Kant saw as the fundamental fallacy behind rationalism, the Tübingen school found in myth. Just as the doctrines of the rationalist metaphysician (viz. the simplicity of the soul) are hypostasizations, so the objects of myth are the products of the religious consciousness, which subconsciously objectifies its own creations into powers ruling over it.

(p.265) Whatever the reasons behind it, Zeller’s tendency to identify the project of historical criticism with Kant was significant for his emerging neo-Kantianism. It meant that Zeller already understood himself to be engaging in a Kantian project in the mid-1840s, a period in his career which is usually understood to be Hegelian. So the neo-Kantianism Zeller will later announce in the early 1860s did not spring fully born out of the head of Medusa. It had been gestating ever since his Tübingen days.

4. From Hegel to Kant

In discussing Zeller’s early critical project it seems we have gone a long way around the barn. For how does this bring us closer to understanding his neo-Kantianism? Although Zeller understood this project in Kantian terms, this was still not enough to make a Kantian out of him. After all, in the mid-1840s, Zeller was as critical of Kant as Hegel. What then happened to push Zeller closer to Kant and further from Hegel? We can answer this question only by going further through and not around Zeller’s early Tübingen years. For it was only by following what happened with his project of radical criticism during these years that we can begin to understand why Zeller finally became disillusioned with Hegel and embraced Kant.

Zeller’s first official public declaration of his neo-Kantianism appears in his 1862 Heidelberg Inaugural lecture, ‘Ueber Bedeutung und Aufgabe der Erkenntnistheorie’, which we will examine closely in Section 6. Suffice it to say for now that Zeller begins his lecture with a denunciation of Hegel’s logic for its confusion of the form and content of knowledge, for its illusion that we can generate content from thinking alone. The great strength of Kant over Hegel, Zeller contends, is that he avoided such confusion and illusion with his distinctions between form and content, understanding and sensibility. What was decisive for Zeller’s move away from Hegel and towards Kant, then, was his endorsement of these Kantian dualisms. So the crucial question is: What led Zeller to affirm these dualisms?

The answer ultimately lies with Strauβ’s and Zeller’s experience with historical criticism, with their motives for adopting it and the conclusions they drew from it. Back in the early 1830s, when Strauβ first attended the lectures of Hegel’s disciples in Berlin, he was struck by their naive assumptions in translating the representations of religion into the conceptual terms of Hegel’s system.³⁹ Rather than subjecting the claims to revelation in the Bible to criticism, the young Hegelians—Marheineke, Gabler and Göschel—simply accepted them at their face value; and so, in translating them into philosophical terms, they were attributing a conceptual necessity and eternal validity to what might prove to be, in the light of historial criticism, a simple falsehood. Determined to avoid such an embarrassing fallacy, Strauβ insisted that one must first subject the Biblical record to historical criticism; only after determining the (p.266) authenticity and reliability of a claim to revelation could one begin to reconstruct it in philosophical terms. But Strauβ’s subsequent investigations into the Biblical record had come to such an overwhelmingly negative verdict—that all the claims to revelation in the Bible were myths, having no historical foundation at all—that there was no justification for a translation of revelation into conceptual terms. The net result of Strauβ’s historical criticism left him staring at what he called “a great chasm, a deep ditch filled with the dragons and monsters of doubt and despair”.⁴⁰ This was his way of referring to Lessing’s famous “broad and ugly ditch” between the facts of history and the truths of reason. The only way to get across that chasm, it now seemed, was through “a leap of faith”, Jacobi’s famous salto mortale.

These results of historical criticism were very bad news for a Hegelian. They meant that the Hegelian dialectic could not bridge the gulf between history and reason after all. The dialectic is an engine designed to cross Lessing’s ditch: it would, if all went to plan, show how the contradictions in the realm of finitude, which is the sphere of the particular and contingent, are resolved in the realm of the infinite, which is the sphere of the universal and necessity. Applied to religious experience, the dialectic is supposed to transform the particular and contingent representations of religious experience into the universal and necessary concepts of the system of philosophy. While some aspects of religious representations are to be cancelled, others are to be preserved, in that wondrous transformative process known as Aufhebung. While the dialectic has its moment of “negativity”, that is, the contradictions inherent in the realm of finite experience, it is also supposed to have a “positive result”, that is, the transformation of the particular and contingent representations of religion into universal and necessary thoughts. But the dialectical engine stalls, shutting down right in front of the ditch it is supposed to cross. For the result of Strauβ’s historical criticism is that there is really no solid spot to jump from; the alleged facts of Biblical revelation are not really facts at all. Hence the dialectic ends, to put it in Hegelian terms, in “abstract negativity” alone, because the content of religious belief is completely cancelled. It leaves us still standing before Lessing’s ditch, that yawning gap between the particular and contingent realm of finite experience and the universal and necessary realm of thought.

That the young Zeller realized the impact of these results for the Hegelian dialectic there cannot be any doubt. We have already seen how he endorsed the negative results of Strauβ’s historical criticism, and how he criticized the Hegelians for naively accepting the Biblical record. But Zeller had gone much further than this: he explicitly criticized the whole procedure of the Hegelian dialectic. In an important article in the Theologische Jahrbücher, ‘Ueber das Wesen der Religion’,⁴¹ he argued that the dialectic is much too reductivist (412–413). We could indeed translate religious experience into the realm of thought, just as we could distil the main thought behind (p.267) a poem into prose. But who would claim that the experience of the poem is nothing but the thought? Like Kierkegaard, who came to similar conclusions around the same time, Zeller stressed how religion is essentially about an individual’s unique and personal experience with God, a dimension left behind by the Hegelian dialectic (399, 404, 409). Most important of all, though, Zeller claimed that the translation of religious representation into philosophical concept is impossible in principle because it requires bridging a gulf between two completely distinct realms (65). The religious representation is in the realm of the unique and temporal; the philosophical concept is in the realm of the universal and eternal. Since they are completely opposed to one another, how could one be transformed into the other? How could the unique and temporal become the universal and eternal? It could be only through a total negation or self-contradiction. What the collapse of the dialectic means, as Zeller puts it, is “the opposition between transcendence and immanence” (65).

We can now see why, already by 1845, Zeller was ready to break with Hegel and side with Kant on the all-important question of the relationship between form and content, thought and sensibility. The Hegelian dialectic could not bridge these dualisms. The most severe examination of the particular, contingent and temporal domain of experience had failed to identify the alleged common content between religion and philosophy, which had been the main presupposition of the Hegelian dialectic. There just was no such content.⁴² Kant, it seemed, had good reasons for his dualisms after all. Rather than trying to leap beyond Lessing’s ditch, the old fox of Königsberg wisely chose to recognize its existence. It was this Kantian lesson that Zeller had learned in the mid-1840s, I suggest, that became the decisive factor in pushing him down the road towards his later neo-Kantianism.

5. Running the Gauntlet, Tübingen to Heidelberg

Zeller’s career began under an unlucky star. The so-called Vormärz period, the years between the Revolutions of 1830 and 1848, which roughly coincided with those between Zeller’s entry into the Stift and his first professorship, were notable as a period of political reaction and conservatism. Eager to prevent revolution in their German homeland, conservative forces—the princes, nobility and clergy—did everything in their power to guard their prerogative and privileges, especially by controlling the press and universities. In 1835 these forces were suddenly mobilized by the appearance of Strauβ’s Das Leben Jesu, which hit the public, to use Zeller’s phrase, “like a bombshell”.⁴³ Strauβ’s book seemed to confirm all the conservative’s worst fears about radical criticism and left-wing Hegelianism. In attacking the historical (p.268) testimony behind the Bible, Strauβ was undermining the very basis of the Protestant faith, and with it the alliance of throne and altar. Somehow, sooner rather than later, this Schwabian “Anti-Christ” would have to be crucified.

The hysterical reaction against Strauβ spread rapidly throughout Germany, quickly reaching even sleepy Tübingen. The first victim was Strauβ himself, who was peremptorily dismissed from his post in the Stift. Now everyone in Strauβ’s circle also stood under suspicion, and they would have to be careful about all they said, wrote or taught. Zeller himself began to feel the heat in 1840 when he gave some lectures on dogmatics to replace another theology professor. For simply stating his sympathy with Strauβ, he was censured by conservatives in the theology faculty.⁴⁴ The censure was a rude shock to Zeller, who now feared that that no Hegelian or Strauβian would ever be promoted in Schwabia. Subsequent events were only to confirm this bleak forecast. When, in 1842, the theological faculty applied to the Ministry of Education for Zeller’s promotion as an extraordinary professor, the request was flatly denied. And when, in 1844, they applied for his promotion in philosophy instead of theology, that too was bluntly refused. Zeller was not alone in such misfortunes. None of Baur’s students were promoted, and some were simply dismissed.⁴⁵

The new winds of 1848 brought the prospects of redemption. Not, however, from anywhere on German soil, but from Switzerland, where a friend of Zeller’s, Friedrich Ries, had secured an offer for him as extraordinary professor of theology at Bern.⁴⁶ Having no other options, Zeller accepted the offer from Bern without hesitation, January 16, 1847. But at first it seemed Zeller would get the same reception in Bern that Strauβ once received in Zurich. When Strauβ was offered a position in Zurich in 1839, the outcry was so great among the clergy and general public that the city council was forced to back down and to retire their just-appointed professor at half-salary. The Strauβ affair threatened to repeat itself with Zeller, because the conservative clergy in Bern raised a clamour and organized a campaign against the “Zeller Religionsgefahr”.⁴⁷ The conservative motion to have Zeller’s appointment revoked was defeated, however, by the deft political manoeuvres of the new radical government in Bern.⁴⁸ Still, such was the animosity stirred by Zeller’s appointment that there were fears for his safety, so that the government found it necessary to provide him with police protection.

(p.269) Eventually, 1848 brought change to Germany too. The University of Marburg, once a provincial backwater, had a new liberal administration eager for reform and new faculty. The administration turned a sympathetic ear to the efforts of Johannes Gildemeister, a professor in the theology faculty, to recruit Zeller.⁴⁹ Not happy with his precarious position in Bern, Zeller told Gildemeister that he was willing to come to Marburg, even though he had been warned about another “storm”. Sure enough, when the conservative clergy found out about Zeller’s appointment, they were furious and organized protests against it. The theology faculty did everything in its power to block the appointment, and prince Friedrich Wilhelm refused to sign the final documents. Only after a massive protest by the liberal assembly did Zeller finally get an appointment, though it was in philosophy rather than theology. Zeller was hired under the condition that he not teach theological topics.

After the initial fire storm, Zeller did manage to settle down in Marburg, where he would stay for the next thirteen years (1849–1862). He was not an especially popular lecturer in Marburg, apparently because his thick Schwabian accent was not so comprehensible there.⁵⁰ Zeller was part of a circle of close friends—the theologian Wilhelm Gildemeister, the philosopher Franz Theodor Weitz, and the historian Heinrich von Sybel—which became known as the “Tuesday club”. The main preoccupation of Zeller’s Marburg years was with the second edition of his Philosophie der Griechen, which had expanded from one volume into three very large tomes.⁵¹

It was most probably during his Marburg years that Zeller completed his conversion from Hegel to Kant. For it was immediately after these years, in 1862, that Zeller would proclaim his Kantianism from the podium in his inaugural lecture at Heidelberg. Unfortunately, it is impossible to determine how and when the conversion took place. None of Zeller’s published letters or writings from the Marburg years explicitly concern Kant’s or Hegel’s philosophy; and there are no notes on Zeller’s lectures on logic and metaphysics from this period.⁵² Since, however, Zeller was most probably a Kantian already in Marburg, we have to revise or qualify the common claim that Lange, who would come to Marburg ten years later, was the father of Marburg neo-Kantianism.⁵³

(p.270) Zeller’s Marburg period came to a close in 1862 when he received an offer from Heidelberg for an ordinary professorship in philosophy. Unlike the Bern and Marburg appointments, there was no political controversy surrounding the offer from Heidelberg. Not only were the 1860s more settled times, but Zeller’s appointment was in philosophy rather than theology, thus avoiding all controversy. As in Marburg, Zeller soon found himself as part of an illustrious circle of friends, including Robert Bunsen, Georg Gervinus and Hermann Helmholtz. With Helmholtz, Zeller would often discuss his new interest in psychology.

It was in Heidelberg that Zeller finally became an integral part of the new up-and-coming movement to revive Kant. Just what his contributions were to this movement we must now examine.

6. Return to Kant

One of the milestones of the Kant revival of the 1860s was Zeller’s inaugural lecture at Heidelberg, ‘Ueber Bedeutung und Aufgabe der Erkenntnisstheorie’, which was delivered October 22, 1862.⁵⁴ It is in many respects the counterpart of Fischer’s 1860 Jena lectures. Like Fischer, Zeller too thinks that German philosophy is in a state of crisis, and that the only way to resolve it is by going back to Kant. Both Zeller and Fischer see the vocation of philosophy as epistemology, “the theory of knowledge” (Erkenntnistheorie), rather than metaphysics.⁵⁵ That message, proclaimed from two prestigious podiums, could not fail to have a wide impact on the philosophical scene in Germany.

The affinity between Fischer’s and Zeller’s lectures raises the question of their relation to one another. Was Fischer an influence on Zeller? Or did they even co-operate with one another? The two men certainly knew of one another, and Fischer’s lecture had been published in 1860, which makes it plausible that Zeller knew of its contents. There is no evidence, however, from Zeller’s published writings or correspondence that he had read Fischer’s lectures. In any case, Fischer and Zeller seem to have come to their conclusions independently, because, for all the similarities in their lectures, there were also interesting differences between them.

These differences become apparent as soon as we raise the question: What, exactly, is the crisis of philosophy for Zeller? Fischer had stressed the danger of obsolescence from the rise of the new empirical sciences, which had left no place for philosophy. While Zeller agrees with that diagnosis, he emphasizes a factor ignored by Fischer: the (p.271) vacuum left behind by the collapse of the great idealist systems. While Fischer had still not abandoned hope of rehabilitating that tradition, Zeller saw its decline as irreversible and final. Philosophy in Germany is now at a turning point, he declares, because it has proven to be impossible to repair the Hegelian system, which has broken down irremediably (489). If philosophy is to go forward at all, it must completely transform itself and start from a new foundation. The best way to determine what that foundation should be, Zeller advises, is to go back to one’s starting point, the place from which philosophy began before the rise of speculative idealism (490). That starting point was, of course, Kant’s critique of pure reason (490). Kant marked a new beginning for philosophy insofar as he made it into a theory of knowledge. Zeller realizes that some of Kant’s predecessors, namely, Locke and Leibniz, were also engaged in the theory of knowledge; but Kant’s great contribution was to make that theory more thorough, comprehensive and systematic; he made the theory of knowledge into the chief vocation of philosophy itself (485). Reviving epistemology is precisely the remedy for philosophy in its present impasse, Zeller contends, because only such an examination will diagnose why the great systems have failed.

Zeller also has a different account of the sources of obsolescence. While Fischer thinks that this danger arises from the special sciences usurping the role of philosophy, Zeller maintains that it derives from them divorcing themselves from philosophy. The relationship between philosophy and the special sciences has veered from its natural course, Zeller says, because the sciences pretend that they do not need philosophy at all, and they even fear that it will interfere with their operations (490). Rather than a divorce, there should be a symbiosis between philosophy and the empirical sciences, where each supports and learns from the other. Just why and how there should be such a symbiosis Zeller does not explain.

The most striking contrast between Zeller’s and Fischer’s lectures concerns their attitudes towards Hegel and the idealist tradition. When Fischer gave his lecture he was still working within the tradition of Hegelian metaphysics; Zeller, however, renounces that tradition as bankrupt from the very beginning. He starts his lecture by declaring it a mistake to assume with Hegel that logic has some kind of content, that it determines the chief structures of the world itself. Logic, for Zeller, has to be completely separated from metaphysics; it is a purely formal discipline, and we have no reason to identify the forms of thought with those of being itself. These forms are the means by which we know being, and we cannot simply equate them with being itself (482). Contrary to the speculative principle of subject–object identity, Zeller lays down the principle that knowing and being are distinct: “The operations of thinking by means of which we know the essence of things are distinct from that which we know through them.” (482) Zeller accepts that formal logic stands in need of some kind of foundation, but he insists that foundation lies with epistemology rather than metaphysics (482). The foundation cannot lie in metaphysics because it, like all the special sciences, presupposes the validity of certain methods that it is the very purpose of epistemology to investigate. Not metaphysics but epistemology is the philosophia (p.272) prima, because we need to investigate the origins and limits of knowledge before we engage in metaphysics (483).

As much as Zeller stresses the need for philosophy to return to Kant, he also maintains that Kant made one fundamental mistake, an error of such prodigious proportion that it was the source of all the errors of speculative idealism. That mistake was his assumption of the unknowability of things-in-themselves (492). Kant made this mistake because he reasoned that if the forms of our faculty of knowledge determine or condition what we know, then we cannot know how things exist apart from and prior to the application of those forms. But there is a non sequitur lurking in Kant’s reasoning, Zeller maintains, because even though these forms originate from ourselves, it is still possible that they conform to things-in-themselves (492). In holding out for this possibility, Zeller was following Trendelenburg’s argument for such a stronger realism in his Logische Untersuchungen. According to that argument, even though the forms of space and time are a priori, arising from the mind, it is still possible for them to apply to things-in-themselves.⁵⁶

Here, then, lay another major difference between Zeller and Fischer. For, though it is not made explicit, Zeller was siding with Trendelenburg in his famous dispute with Fischer, which was just beginning in 1862. No less than Trendelenburg, and contrary to Fischer, Zeller insisted that truth in the empirical sciences requires knowledge of more than just appearances; it is not enough that we know just our representations of things; we also demand that we have knowledge of things themselves. There is a hard element of realism in Zeller’s thinking, which consists in more than a Kantian empirical realism (the conformity of representations with the a priori forms of consciousness), and which demands a stronger kind of transcendental realism (the identification of the objects of experience with a reality that exists independent of them). This stronger realism comes to the fore when Zeller maintains, against Kant, that it is false that sensation gives us only disorganized matter and that all form comes from ourselves (491–492). That Kantian dualism is implausible, Zeller argues, because the particular relations between things in space and time (viz. the clock standing two feet from the window, the ball taking sixty seconds to drop from 6,000 meters) cannot be derived from the general forms of intuition and understanding; these relations are therefore simply given to us, having a reality independent of our consciousness.

Zeller was so confident in his realism that he was not phased at all by the objection that we cannot get outside our representations to see if they correspond with reality itself. We have within our experience a means of knowing whether our representations are only illusions or appearances of things themselves, he reassures us. We do not have to determine the reality of a representation simply from its own content; rather, we determine its reality by comparing it with other representations. We compare different representations of the same sense, representations of different senses, (p.273) and many different perspectives of all the senses; it is only when they all agree with one another that we claim they are of reality itself (493). Besides comparing representations among one another, we have another test for the reality of a representation in the laws of the empirical sciences (494). We ascribe reality to a representation only if it conforms to these laws, and we regard it as illusory if it fails to comply with them.

It is ironic, however, that Kant used just these kinds of arguments to demonstrate the sufficiency of empirical realism. Kant would have agreed with Zeller that we do not have to get outside our representations to determine their reality, and that we have sufficient criteria to do so within consciousness itself; he would have disagreed with Zeller’s conclusion, however, that satisfying these criteria guarantees knowledge of reality itself. For Kant, that extra inference on Zeller’s part would be pure non sequitur. Belief in the correspondence of representations with reality itself was a leap of faith, which no sceptic would be prepared to make or approve.

Some fifteen years later, when Fischer’s dispute with Trendelenburg was a rapidly fading memory, Zeller returned to the topic of knowledge of the external world in some reflections he added to his original lecture.⁵⁷ Zeller here retreats from his earlier position, though he does not recant or attempt to smooth over the inconsistency. Stressing now the role of our senses and physiology as conditions of experience, he maintains that the Kantian conception of the a priori can be extended, so that it applies not only to the forms of intuition and understanding but even to sensation itself (501). We can talk about a priori factors of sensation because it is just a fact—and here Zeller has in mind the experiments of Müller so stressed by Helmholtz—that the quality of sensation depends on the specific qualities of our nerves and brain. We cannot reduce the quality or content of a sensation down to the character of the stimulus, because the nerves and brain so transform the stimulus that their product, the representation, is nothing like them (500). Having emphasized the creative role of the senses in producing experience, Zeller now finds it difficult to retain the realism he had so optimistically affirmed in his original lecture. Although he again insists that the particular content of sensation, and the relations between particular facts in experience, cannot be produced by us and that it has to be given by stimuli outside us (522), and although he again stresses that the definite content of perception simply cannot be explained in terms of the general forms of sensation, intuition or understanding (499, 522), he now explicitly concedes that our representations do not directly reflect things-in-themselves (523). This is because the senses transform what we know, or because the nerves and brain affect the very content of sensation. All that we know directly is simply how these things affect us and how we react to them; and it is impossible for us to get outside ourselves to know the thing as it exists in itself (523). Indeed, the form and content of representations, the role of our own activity and the role of the stimulus in producing it, are impossible for us to separate (523). Although (p.274) Zeller again insists that we can determine the reality of a representation by its coherence with others, it is now obvious that this test shows only facts about appearances—about how the world affects us—and nothing about things-in-themselves. In these reflections Zeller had discovered a point that Lange and Liebmann were also forced to admit: that the thing-in-itself is, however horrible and nonsensical, ineliminable.

Whatever the merits or flaws of his arguments for the unknowability of things-in-themselves, Zeller’s original lecture preaches the doctrine that the assumption of their unknowability was the source of all the errors of the idealist tradition after Kant. Rightly seeing the problems behind this assumption, Fichte, Schelling and Hegel attempted to eliminate things-in-themselves and to explain the origin of experience without having to postulate some mysterious cause behind it. Fichte tried to explain experience on the basis of idealism, by assuming that the opposition between subject and object within experience arises from the absolute ego; but this explanation did not work, because, as Schelling reasoned later, the absolute ego is not really a subject at all, given that the meaning of a subject comes only from its contrast with an object (487). Hence Schelling and Hegel attempted to explain the origin of experience, the division between subject and object, from the standpoint of absolute identity, which is neither subject nor object but the complete identity between them. But, Zeller insists, in ascending to such a high level of abstraction, Schelling and Hegel went beyond the limits of experience itself and indulged in a kind of transcendent metaphysics (488). It is impossible to begin from above, from some abstract absolute standpoint, and then to derive the basic facts of experience from it. In doing so Schelling and Hegel illegitimately attempted to derive the particular and determinate from the universal and indeterminate; they were trying to squeeze blood from a turnip, milk from a billygoat, in the usual rationalist manner. The deductions demanded by the Hegelian dialectic are impossible in principle, because they attempt to derive content from form, the concrete from the abstract (488–489). Here in Zeller’s diagnosis of the problems of Hegelian speculation we can see his reason for thinking that the idealist tradition had collapsed and stood beyond redemption.

It was a central theme of Zeller’s lecture that philosophy had to be first and foremost epistemology because that alone would ensure it against dogmatism and the spectacular errors committed by speculative idealism. Zeller insisted in classical manner, much like Locke and Kant before him, that it is necessary first to examine the conditions and limits of knowledge before attempting to acquire knowledge itself (483). Since the methods we employ determine the results we get, we first need to investigate the value of these methods themselves (481); we need to determine the standards of knowledge, which we derive from the conditions under which the mind acquires knowledge (483). Zeller makes these old points as if they contain profound lessons for future philosophy, as if the speculative idealists had forgotten them entirely, and as if it were for this reason alone they had committed the classical mistakes of rationalist dogmatism. But was Zeller preaching a timely lesson for the fallen or just an old homily for the converted? His argument on behalf of epistemology sounds naive in (p.275) the face of some of the objections made against it. Hegel had lampooned the attempt to learn how to swim before jumping in the water; Lotze had complained about those who forever sharpen their knife but never try to cut anything with it; and Dilthey had contended that we cannot determine the limits of knowing except by undertaking attempts to know and seeing whether they are successful or not. It was a weakness of Zeller’s position that he never replied to these common objections.

For all its naivety, Zeller’s lecture had its merits: within the short span of fifteen pages, it had sketched a new approach to philosophy, a new way forward from the morass of speculative idealism. If Zeller’s arguments were sketchy, hasty and inconclusive, we cannot expect more from a single lecture. The value of the lecture lay more in its proposals and suggestions than its arguments or answers. Last but not least, Zeller’s diagnosis of the failures of the idealist tradition—his claim that the entire tradition came to grief over the thing-in-itself—will prove fruitful. As we shall soon see, it will be made into the central theme of one of the most influential neo-Kantian manifestos of the 1860s, Otto Liebmann’s Kant und die Epigonen.⁵⁸

7. Unfinished Business

For all its richness in content, Zeller’s 1862 lecture had not fully answered the most pressing question of them all, the very question he intended to answer in the first place: How can philosophy avoid imminent obsolescence? Although Zeller had explicitly posed that question, and although he had even suggested an answer, he had not explained or justified it. He had recommended that philosophy should go back to Kant, that it should revive the project of epistemology to avoid the problems of metaphysics. But Zeller had not gone into any detail about how epistemology solves the crisis of philosophy, about how it saves philosophy from redundancy by the special sciences. Zeller finally turned to that task in a later lecture, ‘Ueber die Aufgabe der Philosophie und ihre Stellung zu den übrigen Wissenschaften’,⁵⁹ which he delivered in Heidelberg on November 23, 1868, on the occasion of the birthday of the Prince Karl Friedrich von Baden.

Now, in much more detail than in his first lecture, Zeller sketches the scenario that threatens philosophy. The account he now provides is very similar to Fischer’s. After having freed itself from theology in the modern world, philosophy returned to its old vocation of providing a general worldview, a theory of the universe as a whole. But this conception of its calling was threatened by the growth of the special sciences (447). Each of them had its own special domain, its own unique methodology, which made them independent of philosophy. Since all of reality was carved up among the special sciences, it seemed as if there was nothing left for philosophy to do (450). Philosophy was like that poet who, after finding that the sciences had carved (p.276) up reality for themselves, had nothing more for himself than “the dream world of abstractions”.

Given this predicament, what should be the relationship of philosophy to the special sciences? “What remains left for philosophy?”, Zeller asks (450). The answer to this question will depend on our general epistemological position, he answers. If we assume that there is a source of a priori knowledge within the mind independent of experience, then we can make philosophy the science of such a priori knowledge, so that it is distinct from the special sciences, which all pursue empirical or a posteriori knowledge (448). This, Zeller thinks, was just the position of the idealist tradition, which saw philosophy as an a priori science that could construct all reality by deductive reasoning. But this position has now shown itself to be bankrupt, he claims. That we cannot have a priori knowledge of reality, that we will never succeed in providing an “a priori construction of the universe”, Zeller says, is plain from the failures of Hegel’s dialectical method (449). This method either produces results in conflict with experience or it smuggles in premises from experience to get its results (449).

So, granted that there is no a priori knowledge, granted that all knowledge of the world in some way depends on experience, how do we distinguish philosophy from the special sciences? Zeller assumes that philosophy too will have to adopt an empirical methodology, and that there cannot be any fundamental difference in method between it and the empirical sciences. The problem of defining the difference between philosophy and the sciences has now become all the more acute, however, given that both share the same method and that both depend for knowledge upon experience. We can now see clearly why Zeller thinks that the collapse of idealism left philosophy with an identity crisis: once one rejects the old a priori methods of dialectic or construction, the old border line between the empirical sciences and philosophy disappears. But now that philosophy too has to dwell in the realm of experience, it seems utterly redundant, given that the special sciences have carved up that entire realm among themselves. And so the urgency of Zeller’s question: “What remains left over for philosophy?” (450).

Zeller has three answers to that question, three solutions to the problem of obsolescence, though he never precisely distinguishes them. His first solution reaffirms the main proposal of his 1862 lecture: that the special vocation of philosophy consists in logic and epistemology (459). Now, though, the argument for this proposal is more explicit and better developed. Zeller explains that the activity of thought is the same in all the sciences, and that it is the special task of philosophy to determine the laws of this activity (459). Philosophy determines, in other words, “the general conditions and forms of all scientific thinking” (460). Insofar as it does this, philosophy is logic, but logic understood in a broad sense as the theory of knowledge, a theory whose special concern is “universal scientific methodology” (460). Logic or theory of knowledge does not have to fear redundancy at the hands of the special sciences, then, because it determines the foundation of all the special sciences, and so transcends their particular concerns (461).

(p.277) The second solution to the obsolescence problem is more novel, having no precedent in the earlier lecture. Zeller explains that each of the special sciences has its own fundamental presuppositions and concepts; it uses and applies these presuppositions and concepts to investigate its particular sector of reality; but it does not investigate them itself (462). Such an investigation is the task of philosophy. Zeller explains that physics, for example, uses the concepts of matter, motion and space, but it does not investigate what they mean exactly, whether they have ultimate reality or are only modes of our awareness (462). The same is the case for psychology, which uses the concept of a mind but which does not explain its precise meaning (463). For each of the special sciences, then, there will be a philosophy of that science which has the special task of investigating its fundamental concepts and presuppositions. So, in addition to a general logic which investigates what all sciences have in common, philosophy will also divide into separate parts for each discipline.

Having laid out these solutions to the redundancy crisis, Zeller now goes a step further and suggests even a third vocation for philosophy, yet another task to distinguish it from the special sciences. There must be a science, he reasons, that examines the interconnections between the special sciences, one that transcends their limited boundaries and connects them together into a single theory. The special task of this science will be “the connection of all sciences” (465). It will be a science of all the sciences, a Gesamtwissenschaft so to speak, that summarizes and synthesizes the results of all the special sciences. Zeller calls the subject matter of this science “the infinite ground of all being” (464). What he has in mind, though he does not use that dirty word, is metaphysics. For all his criticism of the metaphysics of speculative idealism, Zeller was not ready to banish metaphysics as such. It’s just that he wanted metaphysics to be based on the methods and results of the particular sciences rather than any a priori methodology.

So, summa summarum, Zeller gave philosophy plenty to do in his scientific age. Philosophy could be logic and epistemology, a study of the conditions and limits of knowledge and science in general; it could be a study of the concepts and presuppositions of any particular science; and it could be a general metaphysics that pulled together all the results of the sciences. What is so striking about Zeller’s general position is that it is still so traditional. Zeller was not willing to abandon the old conception of philosophy as a worldview, a general theory of reality as a whole, the very conception that seemed to have been rendered obsolete. Some of his neo-Kantian colleagues, namely, Lange and Windelband, had already written off this conception as archaic. The precise status of metaphysics remains a troublesome question within neo-Kantianism, with some insisting on its rehabilitation with new methods and others preaching the need for its complete abandonment.

Another remarkable feature of Zeller’s conception of philosophy is that he sees no difference in method or discourse between philosophy and the empirical sciences.⁶⁰ The (p.278) distinction between philosophy and the sciences rests on two factors: its broader scope or generality and its higher level, that is, it is second order, dealing with knowledge of things rather than things themselves. As far as epistemology is concerned, however, Zeller makes no distinction between the Quid juris? and the Quid facti?, the normative and natural. Under the influence of Helmholtz, and in the tradition of Fries, Herbart and Beneke, Zeller continued to see epistemology as a kind of empirical psychology. He shared Helmholtz’s view that if philosophy were to become a science, epistemology would have to engage in the experiments and observations of psychology and physiology. It is ironic, however, that this belief seems to push philosophy even closer to obsolescence, because it makes epistemology, properly pursued, just another form of psychology. As we shall soon see, Windelband will soon press just this point against Zeller.⁶¹

8. A Neo-Classical Ethics

On January 24,1872, after nearly 40 years in the role, Adolf Trendelenburg, professor of classical philosophy at the University of Berlin, died. The University was eager to find someone of similar stature to replace him. They could think of only one person fit for the position: Zeller. The university duly made him the offer of full professorship in July 1872.⁶² To be called to Berlin was the crowning glory for any German academic in the 19th century. The city was the cultural centre of the new Reich, and its university had the most illustrious faculty in Germany. Despite the honour, Zeller hesitated, not least because of fears about his age. He was now 58 and unsure if he had the energy for such a new and demanding role. It was only after Helmholtz, “in the personal service of the government”, travelled to Heidelberg to persuade him that Zeller relented. He began his lectures in the Winter Semester of 1872.

It was a sign of changed times that the outcast in the 1840s had become the celebrity of the 1870s. But Zeller himself had changed too. Although he had never renounced his basic liberal principles, his advocacy of the rights of radical criticism, and least of all his support for David Friedrich Strauβ, Zeller’s political convictions were now more in accord with the new Zeitgeist. Though a Schwabian, Zeller now celebrated Prussia’s rise to power. He was a passionate defender of German unification, and specifically of the Prussian or Kleindeutsch version of it; and he was a staunch supporter (p.279) of Prussia in its war against France. In 1872, in a series of lectures,⁶³ Zeller, like a true liberal, defended the separation of church and state; but this was also a statement on behalf of Prussian Protestantism in its emerging Kulturkampf with Roman Catholicism. Zeller’s cosiness with the Prussian establishment reached its height in 1886 when, on the centenary of Frederick the Great’s death, he published a book celebrating the great ruler as a philosopher.⁶⁴

For his inaugural lecture in Berlin in October 1872,⁶⁵ Zeller returned to the topic of his inugural lecture in Heidelberg ten years earlier: the identity crisis of philosophy. Now, however, Zeller is much more confident that this crisis is finally resolved. There is no danger of obsolescence for philosophy, he assures, because “the German spirit” will never turn its back on philosophy. It will always want to reflect on the fundamental questions of life, and to examine the chief presuppositions of the empirical sciences (469). But the way philosophy should pursue these questions in the future, Zeller declares, will have to be very different from the methods of the past. Rather than attempting to provide a priori deductions from first principles, in the idealist tradition, it will have to investigate the conditions and limits of knowledge according to empirical methods, following the observation and experiment of the new psychology. Never was Zeller so explicit and adamant in his affirmation of empiricism: “Our philosophy should, as far as the nature of its objects permit, take as its model the exact methods of the natural sciences.” (474). And never was he so clear and firm about the realism of his epistemological outlook: “We should comprehend things as they are, and we should not impose on them our thoughts and fantasies; our philosophy should be realism, an image of reality.” (474). This empiricism and realism are fully in accord with the new temper of the times, Zeller reassures us, with the advance of the natural sciences and the growth of technology and industry. In making such a virtue out of following the Zeitgeist, Zeller seemed to have forgotten the programme of radical criticism of his youth.

Zeller’s most important writings on Kant during his Berlin years were two substantial essays on moral philosophy. The first of these essays, ‘Ueber das kantische Moralprinzip’, was read before the Prussian Academy of Sciences in December 1879; the second, ‘Ueber Begriff und Begründung der sittlicher Gesetze’, was read before the Academy of Sciences in December 1882.⁶⁶ The essays complement one another and present a single point of view. In them Zeller sketches his own moral philosophy, one formed chiefly on the basis of his critique of Kant.

(p.280) Zeller’s aim in both articles is to find a middle path between Kant’s formalism and hedonism. Kant had cast his moral philosophy as the only alternative to hedonism. It was either acknowledging duty for its own sake or lapsing into the relativism and egoism of hedonism.⁶⁷ Zeller thinks that there is a middle path between such dire options: the humanist ethic of self-realization or excellence presented by Plato and Aristotle. The great advantages of this ethic are that, by basing ethical precepts on the general laws of human nature, it avoids the emptiness of Kantian formalism as well as the relativism of hedonism. It provides a content for ethics—the needs of human nature—yet it also does not have to surrender to relativism because it bases these needs on universal laws of human nature. In putting forward this classical ethic against Kant, Zeller was following the precedent of his illustrious predecessor in classical philosophy in Berlin: Trendelenburg.⁶⁸ Both Zeller and Trendelenburg therefore represent the standpoint of neo-classicism in modern moral philosophy.

The chief problem with Kant’s ethics Zeller finds in its formalism. Kant had rightly seen that the moral value of maxims cannot be based on their consequences; but on these grounds he wrongly concluded that they should not be based on experience at all. Having rejected experience as an arbiter of moral value, Kant sought its criterion in formal features alone, namely, whether a maxim could be made into a universal law. But this put him in an untenable position, Zeller argues, because the purely formal criterion is empty, capable of sanctioning virtually any content (166–167). This is precisely what we should expect, because once we abstract from all content, as Kant demands, it is no longer possible to distinguish between right and wrong content (164). The mere demand that a maxim be universalizable cannot determine its moral rightness or wrongness alone, given that an egoist is willing to universalize his maxim; it is perfectly consistent for him to will to live in a state of nature where he is ready to compete with others (166–167). If we are to give content to morality, Zeller contends, then we have to consider the purpose to be achieved by it (206). Contrary to his own principles, Kant himself does exactly this, often using teleological reasoning and language. When, for example, he universalizes a maxim, he asks us to consider what would happen—that is, what would be the consequences—if everyone were to do the same (165). And he formulates his principle in teleological terms when he states that every rational being should so act that through his maxims he becomes a member of the kingdom of ends (206).

While Kant’s ethics suffer from emptiness, Zeller holds that hedonism provides no viable alternative to it because it leads to relativism. He agrees entirely with Kant that hedonism, understood as the doctrine that pleasure alone is the highest good, cannot provide a justification for the universality and necessity of moral principles. It is just (p.281) a fact, pointed out by Plato long ago, that people take pleasure in different things, so that we cannot have a universal prescription to strive for pleasure except in a very general and abstract sense (175–176, 210–211).

In both essays Zeller’s repudiation of hedonism is unequivocal, so that it is incorrect to state with Willey: “Zeller stated the eudaemonistic principle unequivocally: Pleasure is good, pain is bad.”⁶⁹ Such a statement comes from reading some sentences of Zeller’s 1882 essay out of context, and from equivocating about the meaning of “eudemonism”.⁷⁰ Zeller distinguishes carefully between a hedonistic eudemonism, which takes pleasure alone to be happiness, and a perfectionist eudemonism, which regards human perfection as the chief source of happiness. More significantly, he distinguishes between a subjective and objective justification of moral actions: where a subjective justification values actions because they are a means to attain pleasure, an objective justification values them for their own sake (209–210). With the subjective justification we regard pleasure as the good, whereas with the objective justification we take pleasure in an action because it is good.

If hedonism ends in relativism, and if Kantian formalism is empty, how do we sustain the universality of moral principles? For Zeller, the answer to this question lies only in the sphere of psychology and anthropology, whose task is to determine “the essential needs and the common laws of human nature” (173). What matters in determining the moral value of maxims should be “the proper nature of human beings, by virtue of their inner, a priori laws” (174). In putting forward this position, Zeller was reaffirming Aristotle’s position in the Nicomachean Ethics that the task of ethics is to determine what is good for man as man. This is an enquiry into happiness, of course, though not happiness in the sense of pleasure but in the sense of self-realization or perfection, that is, what makes a human being excellent or do well at its characteristic activities. Engaging in these characteristic activities brings pleasure, but the pleasure that results from them is not the reason for doing them.

There is a certain plausibility to Zeller’s position, and it is indeed the natural and inevitable one for the classicist to take. But it faced severe problems that Zeller did not squarely face. It is by no means evident that an appeal to human nature or excellence will give the universality that Zeller desires. Does not human nature vary with culture and epoch, and are there not accordingly different, indeed incommensurable, conceptions of human excellence? Herder had already preached that in the 1770s; and Nietzsche was publishing his relativist conclusions from his “historical philosophy” (p.282) just when Zeller gave his first speech before the Academy.⁷¹ Wisely, Kant avoided appeals to human nature because he realized they cannot escape relativism.

Besides relativism, there was another problem with Zeller’s appeal to human nature. Zeller had defended Kant’s distinction between the normative and factual against Schleiermacher’s objections (199–201). But if we accept that distinction, how do we derive the norms of ethics from facts about human nature? Seeing the force of this point, Zeller noted that we could not simply list some common human needs and then rest content with having provided a foundation for ethics (208). We need to know not simply what people want but what they ought to want, a criterion of valid needs; but that leaves the question on what that criterion is based. Zeller had no answer to this crucial question.

Throughout the 1870s, and for decades thereafter, these questions about the foundation of ethics will continue to preoccupy the neo-Kantian tradition. The crucial problem for a Kantian ethics is how it could provide a foundation for morality in the face of two challenges: the apparent formalism or emptiness of the categorical imperative, and the rise of historicism, which seemed to make relativism inevitable. We shall consider some attempts to meet these challenges.