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Jan Baedke, Ruhr University Bochum

The Decline of Neo-Kantianism and Rise of Theoretical Biology in the Interwar Period

This paper investigates different neo-Kantian traditions in early 20th century German-speaking theoretical biology. It especially addresses how and why biologists adopted, reworked, or rejected central tenets of neo-Kantianism in their quest for strengthening the conceptual and theoretical framework of biology. A century after the term ‘biology’ was coined, a number of scholars (e.g., Johannes Reinke, Jacob von Uexküll, Julius Schaxel, Adolf Meyer-Abich) started to argue for the need to develop a theoretical biology (‘Theoretische Biologie’ or ‘Allgemeine Biologie’). The field should serve many goals: conceptual clarification, theoretical ordering, organization of research activities, better communication of results, securing the autonomy of biology from physics, and ultimately, unifying biological research. Due to this diversity of aims, still today, large part of early theoretical biology – including its philosophical underpinning – remains poorly understood. This especially concerns the role of neo-Kantianism in the field.

Therefore, I will trace the impact of classical neo-Kantian debates on early theoretical biology during the interwar period through two complementary approaches: First, I use digital text analysis tools to study the legacy of neo-Kantian authors and conceptual debates about teleology and purposefulness of organisms in influential monographies and book series (e.g., Schaxel’s Abhandlungen zur theoretischen Biologie, and Meyer-Abich’s Bios). Second, I investigate the discussion of neo-Kantian thought by two central proponents of theoretical biology, the philosopher Adolf Meyer-Abich and botanist Emil Ungerer. In the case of Meyer-Abich, we can see the strategy of radicalizing Kant’s transcendental philosophy. By drawing on the discussion of Kant by the physiologist and holist John Scott Haldane and his statement that biological laws are in fact more general than physical laws, Meyer-Abich (1934, 1942) not only tried to secure the explanatory autonomy of biology against physics, but argued that ‘simpler’ physical and chemical laws and concepts can more easily be derived from higher-order biological theory rather than vice versa (he calls this ‘holistic simplification’). In the case of Emil Ungerer (1922, 1926), we see the strategy to replace (neo-)Kantian discussions of teleology and purposefulness by descriptions of the dynamic equilibrium and holistic maintenance of the organization of living systems (i.e. ‘wholeness’; a view that ultimately influenced, e.g., Ernst Cassirer). Finally, by drawing on these two perspectives, this paper argues that while holism (‘Ganzheitsbiologie’) was established as the central philosophical framework for German-speaking theoretical biology during the interwar period, this was only possible through a close dialogue with neo-Kantianism. Ultimately, however, the fields attempt to holistically refine Kantian thought for biology not lasted for long. After reworking or replacing neo-Kantianism, holism was itself replaced by more reductionist theoretical approaches after WWII. This shift would shape the international trajectory of theoretical biology deeply.

Francesca Biagioli, University of Vienna

Cassirer on the Concept of Number: A Neo-Kantian Perspective on Dedekindian Abstraction


The concept of number occupies a special place in Cassirer’s epistemology. Cassirer identified it as the first and paradigmatic example of a concept determined by a serial principle alone in his seminal article “Kant and modern mathematics” (1907), and he placed it at the basis of the logical determinability of the objects of knowledge in his first major epistemological work Substance and Function (1910). Cassirer articulated this view further in the third volume of the Philosophy of Symbolic Forms (1929) by taking into consideration the phenomenological basis of mathematical concept formation. From the broader perspective of Cassirer’s mature philosophy of culture, the concept of number tended to become paradigmatic of a purely symbolic configuration of reality, while retaining its fundamental role in Cassirer’s later accounts of scientific objectivity (see, e.g., the fourth volume of The Problem of Knowledge, from 1940). The unifying tendency of Cassirer’s account, however, is sometimes seen to be in some tension with his reliance on specific notions, such as an ordinal conception of number.

This paper aims to shed light on the peculiar status of the concept of number in Cassirer’s view, by reconsidering the neo-Kantian background of the notion of abstraction that emerges from his account of the structural procedures at work in seminal mathematical theories, from real analysis to projective geometry and foundational inquiries. Whereas the universal concepts of traditional Aristotelian logic are abstracted from a certain number of objects by disregarding their distinguishing characteristics, the logic underlying modern mathematics in Cassirer’s account shows a constructive side of abstraction as leading to relational concepts with infinitely many possible instantiations. Cassirer maintained that this notion of abstraction was foreshadowed in developments of logic and related philosophical disciplines in the Nineteenth century and found its clearest expression in Dedekind’s way to define numbers as sui generis objects that are independent of spatio-temporal notions and uniquely determined in and through their mutual relations.

The first part of the paper will discuss how Cassirer’s view led him to take a different stance from his Marburg teachers concerning the arithmetization of mathematics. Whereas Cohen grounded the notion of number on that of infinitesimal quantity, Cassirer followed the view – shared by most nineteenth-century mathematicians – that a rigorous foundation of analysis ought to avoid all notions of quantity and be carried out by arithmetical means. It will be pointed out that, on the other hand, Cassirer relied on his interpretation of abstraction to provide a new account of the conceptual construction of the objects of experience in the wake of Marburg neo-Kantianism. The second part will discuss the rediscovery of Cassirer’s interpretation in some recent attempts to give a logical reading of Dedekindian abstraction in the context of number theory, and make a suggestion for a possible extension of the structuralist methodology that emerges from Cassirer’s interpretation to other mathematical domains.

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Henny Blomme, KU Leuven

What Is the Scientific Status of Chemistry? Kant and Cassirer on the Construction of Chemical Concepts

In the introduction of this talk, I recall Kant’s evaluation of chemistry as an improper rational science (in his Metafysische Anfangsgründe der Naturwissenschaft – MAN – of 1786) and show how influential Kant’s claim has been throughout the history of philosophy of science. In order to understand Kant’s claim, I shortly deal with its context: the difference between proper and improper science, the presence of mathematics as guarantee of scientific status, and the improbable mathematical constructibility of chemical concepts with respect to the chemistry of Kant’s time.

The introduction allows me to formulate, in the first part, what I see as fundamental problems, not with the project of a metaphysics of natural science as such but with the actual text of MAN. These problems are all somehow linked with Kant’s choice to found a dynamical metaphysics of matter on the claim that its most fundamental characteristic is motion. While the tension that this choice creates has been recognized before, I think that the problems it generates have not been clearly distinguished in the literature. I discuss three such problems: (1) the hard-to-resolve opposition between a metaphysical foundation and an empirical foundation of science; (2) the problem of the distinction between metaphysical “construction” (although this is probably not a Kantian concept) and mathematical construction; (3) the problem of the distinction between material substance and material body.

Commenting on these problems brings me, in a second part, to Cassirer’s (Kant-inspired) criticism on the traditional correlation between a philosophy of science that is bounded by Aristotelian logic and its recognition of the concept of substance as foundational for the sciences. By drawing the ultimate consequences of Kant’s doctrine, following which substance is the categorical expression of only one among many functions of thought with which we bring about unity and objectivity in our cognition, I claim that Cassirer enables us to use the Kant of the first Critique against the Kant of the MAN.

In the third part, I refer to Cassirer’s indications, in the pages of his Substanzbegriff und Funktionsbegriff (1910) that are devoted to chemistry, to contrast his conception of the construction of chemical concepts with Kant’s.

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Jörn Bohr, University of Wuppertal

Why Psychology in Neokantianism? Some Remarks on “Southwestern” Contributions

The task of my argument is not to answer the question posed in the title, but to problematise its implications: Is there a common reason why scholars like Wilhelm Windelband on the side of the “Southwestern school” (or Hermann Cohen on the side of the “Marburg school”) started their careers in academic philosophy with contributions to the so-called “Völkerpsychologie” of the 1870s?

At first glance, one might think that the two neo-Kantian schools had no impact on the further history of psychology and psychology in general. One could say: until Neo-Kantianism there was a history of psychology – after Neo-Kantianism we have psychology as a science which, like mathematics, does not need a historical propaedeutic about its own history because its practice does not depend on the knowledge of its history – like philosophy in its “continental” tradition. To do psychology axiomatically or, spoken less apodictically, to do it experimentally, means to do it without “philosophy” in the sense of “Weltanschauung” or an orientation towards normative values.

But a second look offers insight into the unique situation of late 19th and early 20th century academic philosophy, which in fact in “southwestern” contributions as a philosophy of value wants to participate in a psychology that is not experimentally but historically oriented: Apart from Dilthey’s attempts to build a basic historical psychology to “understand” human historical actors and actions, Windelband offers two alternatives: Psychology either as an auxiliary historical science, as philosophy itself becomes an epistemology of the “historical sciences” (i. e. the humanities), or as mere common-sense psychology for domestic use: we are all human beings, so we easily understand other human beings. But this brought him into serious conflict with what was since then called psychology: firstly, with his own earlier concept, and secondly, with the politics of science in the early 20th century.

The questions that arise from this go deeper anyway. The decision between a philosophy of values or psychology was not just a private question. This gives us an insight into the politics of academics: if, like Windelband, one postulates a realm of absolute values in order to then discover it with the help of philosophy, one has to face the threat that comes from both sides of the natural sciences and psychology because they are not prepared to accept anything like absolute values. In psychology, in its experimental way, one does not ask whether sensual reactions depend on “values”, despite the values on the displays of psychophysical apparatus that the psychologist can read and insert into statistical overviews. The “psychology of buttons and knobs” was a popular and equally debunking joke among traditional philosophers in the early 1900s. The separation of the paths that philosophy and psychology took was public and political. Karl Bühler speaks of the crisis of psychology, and if we assume for a moment that a crisis, as in other critical clinical situations, means a turning-point either to death or to life, then psychology does not undergo such a crisis in neo-Kantianism to its disadvantage – if we do not consider it a disadvantage that psychology tells us nothing at all about historical individuals – just as, on the other hand, we need not expect this of philosophy itself: for it too undergoes a crisis in neo-Kantianism.

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Ralph Cahn, LMU München

Little Affinity, Even Less Appreciation – the Relationship of Chemistry and Philosophy Reflected in the Works and in the Reception of Gustav Tschermak (1860) and Ernst Cassirer (1910)

The relationship between chemistry and philosophy in Germany was rather estranged. At the beginning there was Kant's verdict that chemistry could not be based on geometric relations and would never become a proper science. Hegel tried to overcome this by postulating a logic of chemical transformations using the ancient four elements as classes. Leading representatives of chemistry in France sympathized with positivism, and their German students adopted this attitude: they strove for empirical knowledge in a small area of scientific description, accepted the provisional nature of their results regarding basic concepts such as the element and uncertainty about the nature of chemical bonding. Many rejected hypotheses about the existence and extension of atoms or the spatial structures of compounds. 

How valuable a philosophical approach to chemistry could have been, and how difficult it was to overcome disciplinary barriers, is shown by the writings of the Austrian chemist Gustav Tschermak, who tried to solve the crisis of fundamentals in chemistry. Inspired by Kant and analogous to the work of Clausius for thermodynamics, he developed a system of chemistry from a few assumptions. By introducing estimated relative atomic sizes from density determinations in numerous liquid compounds, it allowed for a geometrical foundation of chemistry. His considerations led to an arrangement of main group elements, which was later to be found in periodic tables, and to the justified assumption that an unknown element with an atomic weight of about 70 should be inserted in the carbon group between silicon and tin, a place which was to be taken in 1886 by germanium (atomic weight 72.6). Although he published his thoughts several times and was able to impress some leading chemists, they remained without resonance. Nevertheless, he received a professorship, founded a journal, a scientific society, and his own institute. A hereditary title of nobility crowned his career as one of the leading mineralogists and crystallographers of his time. His chemical works fell into oblivion.

Even philosophy and chemistry drifted further apart socially and institutionally in the period of Neo-Kantianism, Ernst Cassirer, a philosopher of the Marburg School, took up the topic in 1910. He was able to demonstrate his ostensible goal, i.e. even in a natural science, which places more emphasis on individual objects than mathematics and physics do, concepts are predominantly formed according to mathematical series and are by no means substance concepts in the sense of the older logic. Just as successfully he could show the function of these concepts in the acquirement and ordering of knowledge.

It is hard to say why Cassirer took up chemistry, but two factors come to mind. A changed relationship between chemists and their theories as well as their historical development. And also Cassirer's critical idealism, which, starting from historically relative facts, affirmatively integrates the conceptual provisionality of chemistry into his systematic conception of perception. But even then, the bond between philosophy and chemistry remained flimsy, without continuation.

Robert DiSalle, Western University

Intuition, Evidence, and the World of Modern Physics


Part of the historic influence of Kant’s metaphysics emerged from its unique engagement with the most advanced science of his time—not only with its empirical methods, but also with its implications for metaphysical conceptions of space, time, and causality. Neo-Kantians acknowledged a fundamental challenge, accordingly, to articulate a Kantian interpretation of sciences that represented space, time, and causality in  distinctly non-Newtonian terms, and indeed suggested a radical critique of these concepts as understood by Kant. It was, prima facie,  difficult to defend the the a priori character of the latter, and their ground in a priori forms of sensibility and concepts of the understanding, in the face of contingent and empirical developments in geometry and physics. To this post-Kantian predicament, three paths to a response may be distinguished. Perhaps the most direct was to revise the Kantian a priori to be more general, and therefore compatible with a wider range of empirical possibilities and less constraining to theoretical change. This came at the cost of diminishing the direct engagement with the content of scientific theory that particularly recommended Kant’s view. A second path, especially associated with the logical empiricists, was to “relativize” the a priori, that is, to treat the Kantian forms and categories as imposed by convention on the matter provided by sensation, resulting in formal scientific frameworks connected to the senses by principles of interpretation. Such a conception of the a priori was evidently closely tied to particular scientific theories, and seemed to accord well with many of Einstein’s remarks on the empirical basis of special and general relativity, in particular his reductive analysis of the empirical foundation of geometry, reducing geometrical measurements to observations of “point-coincidences”. But it required a prolonged and doubtful effort to characterize the purely observational basis of theory, in a purely observational language. As a descendant of a classical empiricist project with roots before Kant, yet with contemporary scientific interest, this effort commanded much philosophical attention. Correspondingly less philosophical attention was paid to a third path from Kant, focusing not on the reduction of theoretical claims to sensible elements, but on the connection of theoretical principles with the principles that govern ordinary local experience, their importance to an evidentiary basis for theoretical principles, and their ultimate inability of the latter to impose a priori constraints on larger-scale theoretical pictures of the physical world. This view, associated with (among others) mathematicians such as Riemann and Weyl, is usually not seen as Neo-Kantian, and probably should not be, but nonetheless can be seen to develop from some central Kantian ideas.

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Myriam Gerhard, University of Oldenburg

Hypothesis vs. Fact. Theories of Evolution Following Darwin and Haeckel


It did not take long for some German scientists to value Darwin’s The Origin of Species as the all but despaired of solution of “the greatest mystery of natural science, and to establish one idea, one fundamental law of becoming and being in the organism-world”. Bronn, an established palaeontologist in his own right, published the first German translation in 1860, which sparked a reception that Darwin acknowledged with an almost amused astonishment. Although Bronn did not agree with Darwin in every aspect and voiced his reservations in a commentary to his translation, this did not prevent an enthusiastic reception, especially by scientific materialists. Büchner, for one, welcomed Darwin’s theory as the long awaited for solution to a materialistic explanation of life. After Bronn’s death in 1862 no one promoted the German reception of Darwin’s ideas more than Haeckel. Once again, a meeting of the Society of German Scientists and Medics (GDNÄ) was host to a far- reaching discussion. In September 1863 Haeckel opened the 38rd meeting with a talk on Darwin’s Theory of Evolution. Haeckel aims to elucidate Darwin’s already renowned theory for a mixed audience by focusing on scientific proofs in favour and against this “daring hypothesis”. In his eyes, it is the factual argument that distinguishes Darwin’s theory from previous theories of evolution. Facts, which are not taken for granted by all, as the discussion between Volger and Haeckel shows. The geologist Otto Volger objects to the claim that Darwin’s theory is based upon scientific facts and counters that it is rather a hypothesis born out of want for a better explanation and, certainly lacks a valid empiric evidence. Whether Darwin’s theory of evolution is to be considered to be a fact or a hypothesis, remains a contentious point for the next decades, even beyond Weisman’s declaration of there being no doubt about its factual nature.  

The early reception of Darwin’s thoughts in the German public view – an issue to which every newspaper, every periodical seemed to have a decisive argument – is moulded by the ongoing debate about scientific materialism and the justification of a materialistic principle. Lange’s first edition of his “History of Materialism” with the declared intent to give definite answers to the main contestations of the materialism controversy can be viewed as a turning point. His critique of scientific materialism for the sake of humanity’s progress turns to Kant’s philosophy as a means of mediation between a scientific materialism and an ethic idealism. Lange advocates a naturalism that foregoes the social consequences of a crude materialism. Sciences and philosophy thereafter seem to be repositioned and their respective roles new established. Whether Darwin’s thoughts are one long argument, one holistic theory or a conglomerate of theories is one thread of valid questions I will relinquish in favour of sketching the contestation of the limits of cognition, the balance of evidence and lines of demarcation between sciences and philosophy which engaged scientists and philosophers as much as laymen.


 Bronn, zit. n. Sander Gliboff (2008), 126.

Abstract 8

Marco Giovanelli, University of Turin

Substantiality vs. Variability. Kurd Lasswitz and his influence on Marburg Neo-Kantianism

A trained physicist, Kurd Lasswitz (1848-1910) is best known as a novelist, the father of modern German science fiction, or as a historian of science, the initiator of the modem historiography of atomism. By contrast, Lasswitz's contributions as a philosopher have been largely forgotten. As the paper will show, in the late 19th century, Lasswitz engaged in an intense dialogue with the emerging Marburg school of neo-Kantianism, contributing to shape most of its defining tenets: the interplay between *a priori* and the historical development of science, the relation between infinitesimal and intensive magnitude, the opposition between substance and function. In the mid-1880s, Lasswitz started to implement Cohen's work on the history of the infinitesimal method (1883) in his research on early modem atomism, which, by the end of the decade, grew into a two-volume *Geschichte der Atomistik* (1890)---possibly the most successful example of neo-Kantian historiography of science. Lasswitz combined attention for the historical detail with the search for the abstract "means for thinking" (*Denkmittel*), without which the "fact of science" would be impossible. In particular, Lasswitz regarded Huygens's kinetic atomism as a historical model of a successful scientific theory, shaped by the interplay of two conceptual tools: (a) *substantiality*, the requirement of identity of the subject of change of position over time, which found its scientific expression in the extensive atom; (b) *variability*, the intensive tendency to change in an instant, which found its conceptual fixation in the notion of "differential". By introducing 'variability,' Lasswitz aimed to improve on Cohen's controversial work on the infinitesimal method and, at the same, denounce his failure to recognize 'substantiality' as a separate conceptual tool. Cohen ultimately left the response to his "school" (Natorp 1891, Cassirer 1902, Buek 1905). The paper argues that, by replying to Lasswitz, Cohen's acolytes went beyond Cohen outlining in embryonic form what would become some of the major themes of Marburg philosophy of physics in the 1910s. In the following decades, when the school had dissolved, Cassirer (1929, 1936) often characterized his stance by contrasting it with Lasswitz's opposition between "substantiality" and "variability." Thereby, he recognized not only the theoretical value of Lasswitz's work but also his historical role as an intellectual sounding board for the Marburg school. 

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Gerhard Heinzmann, Université de Lorraine

‘Critique de la Science’ and Conventionalism in France


The members of the French philosophical movement "Critique de la science" (Emile et Pierre Boutroux, Pierre Duhem, Edmond Goblot, Edouard Le Roy, Jules Lachelier, Gaston Milhaud, Henri Poincaré, Félix Ravaisson, Charles Renouvier, Paul et Jules Tannery, etc.) often refer to neo-Kantism in order to point out the methodological limits of a positivism oriented towards Francis Bacon and Auguste Comte. A common feature of these otherwise heterogeneous approaches of the end of the XIXth century, sometimes also called 'new positivism' or, especially regarding their most prominent representative Henri Poincaré, conventionalism, is the emphasis on the indispensability of the creative mind for determining the subject area of the 'exact' sciences: intelligence becomes the rule of action. Kantian categories are then needed where one wants to characterize the obtained law-like generality as objective and not only by a habit remaining in subjectivity. 

Sometimes the consciousness-theoretical component comes strongly to the fore and slides into a Bergsonian spiritualism (Le Roy), which for example Poincaré again rejects as too radical and limits in geometry the creative freedom of convention by a connection to experience.

Members of the movements - many are mathematicians or natural scientists - have indeed rejected the classical theory of the concept of substance and its attributes and have sometimes replaced the concept of substance by the concept of relation, without, however, having penetrated as far as Hilbert's idea, i.e. without having been prepared to renounce genetic moments of explanation in favor of a relational-formal characterization.

The focus of our analysis of the precise historical and systematic relations between this French current and Neo-Kantism will be on two points:

1° Are they really scientists who founded a new philosophical current or is there rather an influence or scientific acculturation of contemporary philosophical discussions?

2° Poincaré and Duhem are considered in the philosophy of the XXth century as pioneers of the linguistic turn and the holism thesis. To what extent can this be considered as the result of the French variant of neo-Kantism?

Abstract 10

Daniel Koenig, University of Siegen

From Magnitudes to Real Numbers. Cantor's and Dedekind's Number Extensions and Their Reception in Neo-Kantianism


In the history of mathematics irrational ratios play a central role time and again. From their discovery by the Pytha-gorean's all the way into the 19th century they are forming, along with negative and complex numbers, a demarcation line for any comprehensive theory of numbers. Although the name arises already in the 16th century, the concept of an irrational number, in contrast to irrational ratios, first achieved full rights through the two new, independently discovered constructions of Georg Cantor and Richard Dedekind in 1872. The significance of these ‘new’ numbers were recognized not only in mathematics but also in Neokantianism. Especially the Marburg School gave attention to the philosophical implications of this mathematical change of concept from magnitudes to real numbers.
The main aim of this talk is to develop and contrast the different receptions within the Marburg School. For this purpose, the talk will outline in a first step the new constructions of Cantor and Dedekind and point out their key aspects from a mathematical-historical perspective. Not only that the infinite as actual infinite plays here a different role as in the pre-19th century context, these constructions are part of a crisis of intuition (“Krise der Anschauung”) within mathematics – culminating in the alleged pure logical deduction of arithmetic (and geometry). The philosophical reception and interpretation of this mathematical development should be subject of the second part of the talk. Concerning the philosophical implications of the new concept of number the talk will highlight the commonalities and differences between the positions of Hermann Cohen, Paul Natorp and Ernst Cassirer. Both – the actual infinite and loss of intuition – pose challenges for a neokantian position. Since they wanted to take the developments in mathematics and the exact sciences seriously, while some of their developments seemed to contradict central assertions of Kant, the Marburg School tried to reconciliate these developments with Kant’s critical project. The talk wants to carve out whether the
different Marburg thinkers can be distinguished from each other on the basis of their different
reappraisal of the fact of mathematics.

Abstract 11

Christian Krijnen, VU Amsterdam

The Problem of Psychology in Neo-Kantianism. On the Relevance of Richard Hönigswald

The view that German idealism from Kant to Hegel and neo-Kantianism only focusses on absolute subjectivity and fails to deal philosophically with concrete subjectivity properly, leaving it to empirical psychology, is widespread. Within contemporary transcendental philosophy, however, Hönigswald is presented as a Kant-oriented transcendental philosopher that paradigmatically succeeded in integrating the 'problem of psychology' into the foundations of transcendental philosophy. Against this background, Hönigswald's transcendental psychology is scrutinized. It is shown why and how the problem of psychology is not a mere empirical issue to be addressed by empirical psychology but part of philosophy as a theory of objectivity, how objectivity relates to the 'monas' (I, concrete subject) as the performing factor of objectivity, and what the basic features of the monas are. Finally, Hönigswald's conception, as a transcendental-idealist philosophy of concrete subjectivity, is assessed with respect to a speculative-idealist (Hegelian) philosophy of concrete subjectivity.

Abstract 12

Hans-Ulrich Lessing, Ruhr University Bochum

Descriptive or Reconstructive Psychology. On Natorp's Critique of Dilthey

On 22nd February and 7th June 1894 Wilhelm Dilthey presented his programmatic treatise Ideen über eine beschreibende und zergliedernde Psychologie (Ideas on a Descriptive and Dissecting Psychology) at the Berlin Academy of Sciences, which appeared in print in the same year in the Sitzungsberichte of the Royal Prussian Academy of Sciences. With this extensive work, Dilthey directly followed up on his Introduction to the Humanities of 1883. The intention of this work, which was planned for several volumes, of which, however, only the first volume introducing the subject has appeared, was the "attempt to lay a foundation for the study of society and history." As Dilthey writes, he summarizes in this book "the whole of the sciences which have the historical-social reality as their object" under the concept of the humanities (I, 4). And since the elements from which history and society are built are human beings, i.e., "psycho-physical individuis" (I, 28), the scientific study of these psycho-physical units of life forms the basal group of the humanities. 

   As Dilthey further states, the theory of psycho-physical life-units is "anthropology and psychology" (I, 29). Anthropology and psychology is, according to Dilthey, "the basis of all knowledge of historical life, as well as of all rules of management and further education of society" (I, 32). Since anthropology is hardly discussed in the course of the argumentation, psychology alone takes over the function of a fundamental science of the humanities in Dilthey's conception and thus becomes a decisive element of his planned foundation of the humanities (cf. I, 33).

   According to Dilthey, psychology must not be a constructive psychology that undertakes to investigate the relationship of human individuals to society by using hypotheses (cf. I, 31). It is not merely a "deepening of man into the contemplation of himself"; it seeks to develop "general propositions" about man that "can become fruitful for the understanding of society and history." (I, 32) Its task in the context of laying the foundations of the humanities requires, on the one hand, an expansion of scope and, on the other hand, a strict limitation to description and analysis.

   The concrete elaborations on the conception of such a descriptive psychology in the context of a critique of constructive or explanatory, i.e., naturalistic, psychology can be found in Dilthey's Ideas.

   Like Dilthey, Paul Natorp argues against the naturalization of psychology. In his book Allgemeine Psychologie nach kritischer Methode (General Psychology by Critical Method) (1st volume, 1912), Natorp unfolds the program of a critical psychology trained on Kant's epistemology, which at first glance appears to the unbiased reader to have a certain closeness, if not affinity, to Dilthey's project of a descriptive-understanding (hermeneutic) psychology. A closer reading, however, reveals that Natorp's intention is quite different from Dilthey's. Yes, one can read Natorp's work - according to my thesis to be explained in more detail in the lecture - almost as an implicit critique of Dilthey's design, since he determines the method of describing mental elements and processes favored by Dilthey as a form of objectification, i.e., knowledge of the law.

   Natorp argues for a psychology that does not want to be an explicit science. Psychology, according to Natorp, should bring the subjective, the "totality of what is experienced" (67), to representation, but without objectifying. Objectification, according to Natorp, is knowledge of law. "Cognition, science as such goes to the object [...]; the cognition of the object is based on the cognition of the law." (143) A law-cognition of the psychic is therefore "not possible other than in the sense of objectification." It can thus "not lead to the goal of a peculiar science of the subjective." (143)

   As an alternative to explanatory, naturalistic, or natural-scientific psychology on the one hand, and descriptive psychology and phenomenology on the other, Natorp develops the idea of a "reconstructive psychology" (172f., 175ff.), the basic idea of which - in short - consists in the "'reconstruction' of the immediate in consciousness from what has been fashioned out of it: from the objectivizations as carried out by science, and before all science, without any conscious intention, by the everyday mode of imagining things." (177) Reconstruction in Natorp's sense is insofar "a complete and pure reversal of the procedure of objectifying cognition, scientific as well as pre-scientific." (178)

Abstract 13

Sebastian Luft, Marquette University

Factum and Region. Neo-Kantian and Phenomenological Paradigms for a Philosophy of Science.


The Marburg School of Neo-Kantianism and the Phenomenological Movement, respectively, have worked out very elaborate theories of science, to the extent that these efforts were perceived by some to be mainly geared at philosophy of science (which would be misleading for these movements as a whole, of course).  Nonetheless, these efforts are worth a closer look for the sake of a comparison.  Famously, the Marburg School starts out from the “factum of the sciences” (Faktum der Wissenschaften) in each domain of cultural work and attempts to reconstruct the (broadly speaking) subjective “work” that went into constructing the different sciences serving these distinct cultural domains.  The Neo-Kantians thus start out from an existing factum and work their way backward from there to the “conditions of the possibilities” of the sciences lying in subjective achievements.  The Phenomenological Movement, on the other hand, starts out from “evidences” given in subjective experiences; these evidences have the function of guiding clues (Leitfäden) for the constitution of regions of experience (nature, spirit, most generally), which can be grouped under so-called “regional ontologies.”  These regional ontologies are the basis for an investigation of the subjective achievements involved in the constitution of the spheres of reality, nature and spirit, which can be separated only abstractly, to be sure.  In this talk, I would like to investigate these two different paradigms (Factum and Region) and assess them for their potential success in grounding a philosophical theory of science.

Abstract 14

Rudolf Meer, University of Graz

Between Physical and Chemical Atomism. On the Status of Chemical Elements and Classifications in Helmholtz and Cassirer


Despite a quiet but successive revolution in chemistry in the second half of the 19th century, there is a consensus that the unity of the atom and its mass (or weight) is the basis of both the chemical elements and the entire chemical classifications. Chemists—with few exceptions—prefer a chemical atomism, which becomes the criterion of demarcation from philosophy and mathematics. At the same time, however, the majority remains indifferent or skeptical regarding physical atomism (for the German-speaking area among others Lothar Meyer, August Kekulé or also August Wilhelm Hofmann). In this sense, chemical formulas and their illustrations (especially the periodic table of elements from 1869) represent above all research-useful hypotheses that were instructions for action and educational tools. 

Even though chemistry and its specific nomenclature play a subordinate role within the framework of neo-Kantianism, both Hermann Helmholtz and Ernst Cassirer take up the question of the physical existence of atoms. Starting from chemical practice, they develop different philosophical justifications for chemical classifications. Helmholtz defends a constitutive conception of physical atomism until the end of the 1860s, while Cassirer develops a hypothetical or regulative one at the beginning of the 20th century.

Thesis1: Despite all differences in the revision of Kant’s philosophy (of chemistry), both Helmholtz and Cassirer further interpret Kant’s concept of law. By focusing on his division between philosophy and the sciences (chemistry / physics), they take up the critical potential that Kant’s approach offers.

Thesis2: The two interpretations of physical atomism illustrate the heterogeneity and development of neo-Kantianism from the middle of the 19th to the beginning of the 20th century. Completely committed to a mechanical worldview, Helmholtz continues to hand down Kant’s constitutive concepts of understanding with his dual mechanism of force and matter. On the other hand, Cassirer interprets the classifications of chemistry as regulative concepts. Thus, he makes a less strong claim and takes the hypothetization of science more into account. 

Thesis3: Even before the experimental proof of the atom, the status of elements and chemical classifications are established based on its hypothetical assumption. Therefore, the nomenclature of chemistry builds a paradigmatic example engaging scientific and philosophical problems. 

For this reason, the paper follows the methodological approach of &HPS and combines two different standpoints: (i) philosophical history of science (PHS) and (ii) historical philosophy of science (HPS). Following the first approach, historiographic questions are reconstructed, which allow an understanding of the resulting philosophical concepts, as well as the development of neo-Kantianism. Following the second approach, physical atomism (as a philosophical problem) is investigated considering the historical development of chemistry and how Helmholtz and Cassirer apply their philosophical theories to the scientific problems. Only the integration of both approaches enables to draw a comprehensive picture of the status of chemical classifications and the concept of element.

Abstract 15

Alfred Nordmann, University of Darmstadt

Kantian Themes in Impure Science

 (Neokantianism and the Sciences of Technology and Synthetic Chemistry)


„We may lay it down as an incontestible axiom, that, in all the operations of art and nature, nothing is created; an equal quantity of matter exists both before and after the experiment; the quality and quantity of the elements remain precisely the same; and nothing takes place beyond changes and modifications in the combination of these elements.“ Arguably, with this statement of a conservation law, Antoine Lavoisier founded modern chemistry not just as a body of theory but also as experimental practice in a laboratory that is organized around measurements of weight. The statement also indicates a parting of the ways.

In technology and nature, nothing is created - this is an axiom and trancendental principle or condition of possibility for picturing the world. As such, it is an invitation to Kantian reconstructions of theoretical chemistry with its periodic table of elements, with its empiricist approaches to molecular modelling.

In technology and nature, nothing is created - this rings obviously false in the ears not only of „pre-modern“ chemists like Priestley, but also in synthetic chemistry with its more than 14 million new compounds since the time of Lavoisier. As Bernadette Bensaude-Vincent and Jonathan Simon have shown, chemistry is an „impure science“ precisely because it alternates so quickly and easily between a theoretical mode in which „Stoffe/substances“ are represented as a purified material substrate of a chemically composed world and a technical mode in which „Stoffe/substances“ are just the impure superficial stuff that is subject to experiment. Are there (Neo)Kantian reconstructions of technical creativity in synthetic chemistry or other 19th century fields of technological inventiveness?

It is a commonplace of the philosophy of technology, that traditional epistemology and metaphysics, including the whole tradition of Kantianism have for the most part neglected engineering and technology. The problem of knowing the world through making and building did not become a „problem of philosophy.“ Asking whether 19th century Neokantianism provides a theory of synthetic chemistry or engineering sciences or whether it played any role in the formation of these research fields will therefore leave us pretty much empty-handed. To be sure, the beginnings of the philosophy of technology interpret the history of the increase of technological powers in mostly Hegelian terms.

If one assumes however, that Kantianism - like Darwinism or Freudianism - was „in the air“ and provided a general background to the question of what is science, it is possible to discern vaguely Kantian themes in early attempts to establish engineering science. Here, the Theoretical Kinematics by Franz Reuleaux can serve as a paradigm. Without referring to Kant or Kantianism, Reuleaux‘s idea of a science and general theory of the machine highlights on the one hand how it differs from theoretical representations of natural phenomena, and on the other hand how it advances the domestication through confinement (Beschränkung) of brute nature. Indeed, Reuleaux‘s theoretical kinematics and cultural history of technology end up reinventing from an engineering point of view Lavoisier‘s edict that „nothing takes place beyond changes and modifications in the combination of […] elements“ and that we are, in a sense, the lawgivers of nature. 

Abstract 16
Abstract 17

Volker Peckhaus, University of Paderborn

(Neo-)Kantian Foundations of Foundations: The Göttingen Case


The formalistic approach to the axiomatization of mathematics suggested by the Göttingen mathematician David Hilbert (1862-1962) at the beginning of the 20th century codified the new structural view on mathematics predominant today. The foundation of a mathematical structure was seen as a problem to be solved within the structure, i.e., using the features of the structure itself. This was celebrated as an emancipation of mathematics from philosophy, although it could itself be regarded as a philosophical position. In this situation the Neo-Friesian philosopher Leonard Nelson (1882-1927) and his mathematical teacher Gerhard Hessenberg (1874-1925) created a Critical Mathematics in a Kantian spirit in order to provide a philosophical foundation of structural mathematics which was also regarded as suitable to justify quasi-axiomatic systems outside mathematics. The story may cast fresh light on the relation between philosophy and mathematics, on different attitudes towards foundations between philosophers and mathematicians, and the influence on social factors in foundational debates.

Helmut Pulte, Ruhr University Bochum

Clouds over Classical Physics? Some Neokantian Perspectives on Kant's Preeminent 'Science of Principles' and 'System of the Empirical'


It goes without saying that for Kant, alongside pure mathematics, mathematised physics was at the centre of what he called the ‘fact of science’. For physics, he spelled out this fact in the Metaphysical Foundation of Natural Science (1786) by a mechanistic programme, according to which all phenomena of external nature can and must be explained at the end of the day by (dynamical) matter in motion. This is what best makes explicit his fundamental understanding of science as a system, based on unshakeable mathematical principles. Already J. F. Fries, belonging to the first generation of Kantian philosophers of science, recognised that this extremely ambitious programme could only be pursued by a methodological and heuristic interpretation of Kant’s idea of ‘proper science’.  

The Neokantian orthodoxy of a ‘Back to Kant’, however, seems to have overlooked this possibility and apparently defended the stricter programme of Kant himself, though important premises of it became more and more problematic in the course of later scientific developments and philosophical enquiry. From a more philosophical point of view there were more ‘clouds over classical physics’ as those detected by William Thomson (Lord Kelvin) at the turn of the 19th to the 20th century: Not only did it seem exceedingly difficult to integrate areas like electrodynamics and thermodynamics into a unitary system of theoretical physics. It became also increasingly difficult to defend Kant’s traditional ideal for other reasons. To mention only a few: The conceptual pluralisation of theoretical mechanics, the development of new geometries, the growing importance of experimental practice for the self-understanding of physics or the growing desire within physics to gain interpretative sovereignty with respect to metatheoretical questions independently of ‘school philosophy’ also were important stumbling blocks for a more traditional Kantianism. Furthermore rather ‘external’ disputes about a hard-boiled materialism or E. DuBois-Reymond’s ‘Ignorabimus’ brought critical enquiries concerning the legitimate philosophical claims of mechanism onto the agenda. The intellectual impact of the ‘Darwinian revolution’ manifested itself, among other effects, in the question of how far the fundamental principles of physics might be subject to change along with the cognitive structure of man.

All these developments led to a fundamental change of the image of physics, its prototypical and systematic character and the epistemic status of its principles, both in science and in important philosophical strands during the second half of the 19th century. The main aim of my paper is to examine to what extent representatives of Neokantianism have perceived these philosophical challenges and what, if any, their philosophical responses in exchange with physics were. Far from understanding Neo-Kantianism as a homogeneous movement, I will try to identify different lines of development and to check whether there was a fruitful interaction with physics (or not). Guiding for my enquiry is the question of the fate of physics as a system and its first principles as aprioris of our knowledge of nature. The main focus will be on the period of ‘classical physics’, i.e. the time before Einstein’s theories of relativity and new quantum physics came up, because these later developments brought about new and fundamentally different challenges from those indicated above. The Marburg tradition of Neokantianism will be a ‘natural victim’ of my attempt, while other important representatives (such as perhaps O. Liebmann, A. Riehl or H. Rickert) should not be completely ignored. Whether this will ultimately lead to a more or less conclusive overall picture seems questionable, but must remain open at present.

Abstract 18

Dolf Rami, Ruhr University Bochum

The Legacy of Kant’s Conception of Existence

In this paper, I will show to what extent Kant’s conception of existence influenced certain important thinkers of the 19th century. More specifically, I will show which influence Kant had on the views of existence of Herbart, Frege and Schröder and that at least two different traditions of the development of Kant’s view of existence have to be distinguished. Firstly, I will very briefly lay out Kant’s earlier and later view of existence expressed in Kant (1763, 1781/87) and his lectures on
metaphysics and the philosophy of religion. Secondly, I will show in which sense Herbart transformed in his logic Kant’s earlier view. Thirdly, I will argue that there is a direct conceptual path from Herbart to Frege via E. Reinhold and I will also point out significant differences between the formal and informal conception of existence in Herbart and Frege. Finally, I will argue that Schröder externalized in his logic of classes a blend of Kant’s later and earlier view and lay out what the main difference between his views and the view of Frege are.    

Abstract 19

Stefan Reiners-Selbach, HH University Düsseldorf

The Challenge of “Leipziger Völkerpsychologie”? The Neokantian Reception of Wundt’s “Psychology of Peoples”

Wilhelm Wundt’s monumental ten-volume work on Völkerpsychologie (1900-1920) was supposed to provide the necessary complement to his individual psychology for dealing with higher mental processes. Such a “psychology of peoples” was first developed by Moritz Lazarus and Hajim Steinthal in the middle of the 19th century as the empirical study of the “mind of a people” (Volksgeist) or “objective spirit/mind” (objektiver Geist). While their earlier version of Völkerpsychologie deals with the entirety of structures, objects, and laws of social and cultural reality, Wundt aimed to render it more accurate by reducing its scope to language, art, customs/ethics (Sitten), and myth. Still, it encompasses subjects, which are usually ascribed to other humanities such as history, linguistics, ethnology, and even philosophy.

While Wundt’s view that psychology ought to be the basis of the humanities might already have been controversial to some, the incorporation of humanist subject matters into psychology, seemingly tackling them with psychological methods, should have run contrary to Neokantian programmes. At a time when on the one hand professors of philosophy demanded that psychologists should no longer be able to acquire philosophical chairs in Germany and on the other hand Wundt saw psychology in a struggle for existence, tensions were high. How did the Neokantians then rise to the challenge that Wundt’s Völkerpsychologie poses? Surprisingly, they rarely did at all. This talk will offer a possible explanation as to why that might be the case and give a brief overview of the Neokantian reception of Völkerpsychologie. I will argue that Wundt’s reduction of Völkerpsychologie’s extent made it mostly irrelevant for Neokantian questions. Therefore, Neokantians dealing with Völkerpsychologie mostly referred to Lazarus and Steinthal, whose programme might even be called Neokantian avant la lettre.

Abstract 20

Christian Reiß, University of Regensburg

Laying the Foundation for a Science of Life: the Role of Neo-Kantian Philosophies and Philosophers to the Project of a “Allgemeine Biologie” and a “Theoretische Biologie”, 1880-1914

The time around 1900 saw the formation of a discourse on the new foundations of a science of life in the German-speaking world. Under the term “Biologie”, the increasing heterogeneity of knowledges and methods in the study of living phenomena that researchers used and produced in various institutional settings created the feeling of crisis. The discontent with the synthetic offers of physiological physicalism and evolutionary theory called for a new foundation of a science of life. Inspired by other natural sciences but also by philosophy, the last two decades of the 19th century saw both systematic discussions of the problems and concrete proposals. At the turn to the 20th centuy, “allgemeine Biologie” and “theoretische Biologie” emerged as headers for these approaches. But discussions already began in the 1880s. From early on, vitalistic conceptions from the 18th century saw a renaissance under the term neo-vitalism. These were first inspired by the structure and properties of cells and particularly their protoplasm. Soon, especially experimental methods produced more and more results that fueled the critique of mechanism. At the same time, the alternative foundations proposed became more elaborate. While empirical findings played an important role in this process, the critiques were also based on philosophical considerations. Particularly Neokantianism turned out to be a crucial reference in this respect. Often based on idiosyncratic readings by life scientists, a re-appreciation of Kant’s “Kritik der Urteilskraft” promised the foundation of biology as a science independent of physics or chemistry.

In my talk I map out this discourse between 1888 and 1914 from the side of the life sciences. I will identify the different empirical research programs and the philosophical traditions they mobilized to offer a differentiated contextualization of the Neo-Kantian tradition. I pay particular attention to the social dimension of the field and its consequences for university teaching to allow for the assessment of the influence of Neo-Kantian philosophies on the generation of zoologists and botanists trained in the time between 1900 and 1914.

Abstract 21

Gregor Schiemann, University of Wuppertal

Hermann von Helmholtz on the Unification of Science

The striving for a unification of the sciences, which characterises Hermann von Helmholtz's scientific work throughout, concentrates on mathematical physics, is oriented towards a mechanistic world view and is subject to a process of increasing hypothetization. One starting point is his formulation of the law of energy conservation, one end point are his ideas on the principle of the least action. The physical efforts towards a formally founded unity are accompanied by manifold of synthetizations in special fields such as optics, acoustics and electrodynamics. The quest for unification is in tension with the specialisation of the sciences, which was already progressing at that time, and finds its limit in the difference to the humanities recognised by Helmholtz and still relevant today.

Abstract 22
Abstract 23

Tim-Florian Steinbach, University of Wuppertal

Technology in Neo-Kantianism: Challenge in Times of Cultural Change or Just a Tool for Applied Sciences?

In the 19th century, thinking about technology was not yet a genuine field of work for philosophers, but rather for engineers and Neo-Kantianism is not an exception. Neo-Kantianism did not develop its own philosophy of technology, nor does it appear to have engaged systematically with technology. This may seem surprising due to the fact that Neo-Kantianism certainly acknowledged the advances and achievements of technology. At first glance, technology seems to be only a tool for applied sciences for most Neo-Kantians. Initially, technology is not a separate field on a par with other cultural fields like art, ethics or religion. Technology is a means to an end but what this end means is not a question of technology itself. Its value is given from outside. And this is necessary, for technology is often seen in the 19th century – also by Neo-Kantians – as an engine that promotes social inequality. Seen from this angle, it is considered in more detail less in the context of scientific theory than in social philosophical and pedagogical writings. In the tradition of Neo-Kantianism it is first Ernst Cassirer who ascribes a constitutive function to technology, on an equal footing with other areas of human conception of reality. It his engagement with technology that raises it to a philosophical level.

Michael Stoeltzner, University of Carolina

Positivism and Empirical Realism - Episodes from a Changing Relationship

In his 1932 article “Positivism and Realism”, Moritz Schlick argued that accepting the principle of verification reconciled any reasonable positivism with the kind of empirical realism developed in Kant’s critical philosophy. Schlick’s former teacher Max Planck, who had been combatting Machian positivism since decades, agreed, reminding Schlick merely of the historical and social dimensions of science. Is thus one of the alleged, purportedly faulty dogmas of Logical Empiricism already strong enough to level well-entrenched philosophical frontlines between the scientific world conception and a philosophy of science that remained indebted to Kantianism? Or was Planck simply a shoddy philosopher no longer walking in Helmholtz’s footsteps? But there are similar exchanges in the 1930s, among them Philipp Frank’s highly positive, if slightly ironic, review of Cassirer’s book on determinism and indeterminism. Had we simply reached a time of unity in the face of fascism and war that was even broader than Neurath’s encyclopedia?

The goal of my paper is to look at the changing relationship between positivism and empirical realism by describing significant changes in these basic concepts and in their roles for the self-identification of philosophical movements. During the 1920s and 1930s, historical narratives figuring these concepts were repeatedly employed to justify Logical Empiricists’ focus on issues key to the sciences at the expense of maintaining a systematic ‘philosophical’ approach. This was especially the case after debates among scientists threatened a return of outdated metaphysics. These eventually convinced the movement to abandon the label of positivism because it had developed from a general commitment to anti-metaphysics and renewed enlightenment into a phenomenalist doctrine they opposed. Given these developments, one may wonder – somewhat ironically – whether the opposition of Logical Empiricism to Kantianism touted in the 1929Manifesto was not one of those dichotomies familiar from the history of science that – as young Neurath remarked – rather served pugnacity than historical analysis. My point is not to continue the impressive scholarship on the neo-Kantian roots in Logical Empiricism that has overcome the Austrian narrative of the Manifesto. It is rather to focus on the different discursive modes and the different ways to employ historical narratives on both sides. Neo-Kantians often professed allegiance to Kant’s philosophical heritage even though it had become largely emblematic. Logical Empiricists, on their part, initially continued the discourse among scientist-philosophers shaped by the generation of Mach and Helmholtz. While neo-Kantians emphasized the autonomy and systematic ambitions of philosophical analysis, those continuing Mach’s original positivist project emphasized specificity and a broader scientific approach in which Mach’s naturalism was replaced by modern logic and French conventionalism. This development can also be seen in the surprisingly different understandings of “wissenschaftliche Philosophie” as systematization of knowledge prevailing in the late 19th century and as one of several methodological approaches towards a new discipline “philosophy of science” advocated by Reichenbach in the 1930s – at the same time when he still write a rather positive paper about Kant and the natural sciences.

Abstract 24

Marco Tamborini, University of Darmstadt

Organic Form and Teleology: The Principle of Analogy

Over the last decades, our understanding of the Kantian and neo-Kantian influences on 20th-century life sciences has growth exponentially. Studies have investigated in-depth the importance of the Kantian framework for the development of, for instance, twentieth-century evolutionary biology and paleontology.

What is still lacking, though, is a close analysis of how the Kantian vocabulary has been used and implemented in actual biological practice. In my presentation, I investigate the intertwinement of Kantian framework and biological practices in early twentieth-century study of form, or morphology. Particularly, I focus on definition of form as construction proposed by several German-speaking biologists at the beginning of the twentieth century. These biologists based their investigations on Kantian and neo-Kantian bio-philosophy. According to this broader philosophical framework, teleology and mechanism could not simply be divided in order to understand the dynamics of form development. Several biologists used this philosophical framework as a platform for developing a technical and engineering understanding of nature.

First, I will briefly recall the broader panorama of twentieth-century morphology. Second, I delineate the main features of the notion of form as construction as proposed by German anatomist Hans Petersen. Third, I concentrate on the notion of teleology as emerged from Petersen’s and colleagues research agenda. Petersen famously defined a purposive form as one that can be achieved under a “maximum-minimum condition”. Finally, I will reflect on the principle of analogy as a guiding principle in early twentieth-century form research.

Abstract 25

Georg Toepfer, ZfL (Leibniz Zentrum)

Philosophy of Biology in Neokantianism ‒ A Comprehensive and Systematic Account Parallel to and Apart from the Formation of the Field 

Although it was not presented as a coherent work, philosophy of biology within the Neokantian movement had a systematic structure and was comprehensive in its scope. Based on Kant’s philosophy of “organic beings in nature”, the Neokantian account was organism-centered and defended teleological reasoning as biology’s most fundamental methodological approach. One of the central claims was that the very concept of the organism was essentially teleological, i.e. built on the concept of purposiveness (Liebmann 1899). Consequently, biology was defined as the science that deals with physical bodies that consist of parts being connected in the form of a “teleological unity” (Rickert 1902). Following the ideas of Kant’s philosophy, Neokantian thinkers were not anti-mechanistic but tried to reconcile teleology with mechanism by claiming that the concept of the organism that refers to holistic, teleological structures stands at the very beginning of biology’s research agenda and that only their explanation proceeded in mechanistic terms without rendering teleology obsolete. Thus, by presupposing the concept of the organism as a teleological starting point, teleology was thought to be involved in any mechanistic analysis of biology (Kroner 1913; Bauch 1917). Going beyond Kant’s individualistic perspective of the organism, the Neokantian philosophers embraced the evolutionary turn in biology and conceived of biology as a “historic science” (“historische oder individualisierende Naturwissenschaft”; Rickert 1929). Based on the different modes of understanding in history and science, biology was divided into a historic and a scientific part, the one devoted to an individualizing account of the changes in organic forms, the other to an explanatory approach by identifying general laws (Rickert 1902; 1913). However, the Neokantians not only analyzed biology’s internal structure but also contributed significantly to an understanding of the relation of biology to other sciences and the humanities. In his extensive critique of the philosophy of life popular in his time, Heinrich Rickert for example, argued that life itself cannot be a cultural value and no principles for the understanding of the human sphere can be derived from biology. Rickert’s central concern consisted in a conceptual differentiation between a value-free scientific concept of life and the “cultural values” to be analyzed in cultural studies (Rickert 1911).

In my talk, I will reconstruct the Neokantian philosophy of biology in its wide scope and clear structure. I will also try to explain why it had no significant influence on the formation of the classical German tradition of the philosophy of biology that also took place in the first years of the twentieth century. The heterogeneous field that called itself “Theoretical Biology” (Reinke 1902; von Uexküll 1920) or “Philosophy of the Organism” (Driesch 1908) was at the same time more empirical and more speculative in its orientation than the Neokantians were. In retrospect, their metaphysical restraint proves to be an advantage: After all vitalistic principles such as Driesch’s “entelechy” have long been expelled from biology, it still remains an important task to understand the logic of teleological reasoning which was the most important point in the Neokantian philosophy of biology.

Abstract 26

Michele Vagnetti, University of Florence

Hermann Lotze and His Reception by the Neo-Kantians

Because of his dual interests, both in medicine and philosophy, Rudolph Hermann Lotze influenced not only the logical and philosophical debate, but also the physiological and psychological ones. It is now well known that Lotze’s second Logik (1874) was a fundamental book for Otto Liebmann and the neo-Kantian Baden School. The aim of my talk is to shed light on the role that Lotze played in the physiological and psychological field, taking the case of Hermann von Helmholtz as an example. The empirical theory of vision that Helmholtz presents in the Kant-Rede “Über das Sehen des Menschen” (1855) is influenced by the theory of local signs that Lotze developed in his Medicinische Psychologie (1852). The fundamental conceptual points that Helmholtz draws from Lotze’s Medicinische Psychologie to develop his empiricist theory of vision are twofold: (i) local signs are additional sensations produced by retinal stimulation, eye movements, and head and body position; (ii) the center of the retina is the place to which all local signs refer. The world represented in our visual field is not an exact and faithful copy of the external world precisely because consciousness is not a mirror reproducing nature. The visual field is a set of images, representations or mental symbols that serve to orient us in the best way in the world of external objects. Based on the theory of local signs Helmholtz diverges from both Kant and Johannes Müller, who attempted to ground Kant’s theory on an anatomical-physiological basis. Visual space, Helmholtz asserts, is not immediately given as the form of the external sense, but is empirically constructed on the basis of eye movements and tactile sensations. The act of vision is, according to Helmholtz, a purely psychological act and not determined by innate anatomical-physiological mechanisms.

Abstract 27

Marij van Strien, University of Wuppertal

Did Thermodynamics and Statistical Mechanics Weaken the Classical Worldview?

The physics of the eighteenth and nineteenth century is usually referred to as ‘classical physics’, and more generally, in this period the classical or Newtonian world view is thought to have been dominant. The main characteristics of this world view are determinism, mechanism, Euclidean space and time, as well as a sense that physics rests on fixed and secure foundations. It is commonly thought that this world view only came to an end through the revolutions in physics in the early twentieth century.

However, a look at the development of thermodynamics, the kinetic theory of gases and statistical mechanics complicates this image, for a few reasons.

First, the development of the kinetical theory of gases and statistical mechanics led to the idea that laws of physics could have a statistical rather than an absolute validity. In particular, in the analyses of Maxwell and Boltzmann, the second law of thermodynamics holds only statistically.

Secondly, the kinetic theory of gases led to problems for the conception of matter. Within the kinetic theory of gases, it was possible to derive the number of degrees of freedom of atoms on the basis of the specific heats of gases. The obtained result was hard to reconcile with results from spectroscopy, which indicated that atoms were capable of internal vibrations, requiring a higher number of degrees of freedom. The structure of atoms and thereby the very nature of matter thus became a scientific problem.

Finally, towards the end of the nineteenth century, there was increasing opposition to the idea that all of physics should be reduced to the mechanics of atoms. Physicists such as Mach, Duhem and Ostwald argued that the attempts to give mechanical explanations of all physical phenomena led physicists to devise speculative and needlessly complicated models which often remained unfruitful. They furthermore argued that there may well be natural phenomena which were fundamentally irreducible to mechanics; an important case was the irreversible behaviour described by the second law of thermodynamics.

The problems with the conception of matter and the doubts about the mechanical foundations of physics increasingly led to the idea that the nature of reality is unknowable and that physicists should restrict themselves to describing observed phenomena, rather than concern themselves with metaphysical questions.

Thus, by end of the nineteenth century, commitments to determinism and mechanism had weakened and the foundations of physics were under debate. This could be interpreted by saying that at this point, the classical worldview was already weakening. But it may also be taken as an occasion to reflect on the concept of classicality itself. As Richard Staley has shown, the term ‘classical physics’ only emerged in the early twentieth century; he therefore speaks of the ‘co-creation’ of classical and modern physics. It is important to be aware of the rhetorical purposes which the terms ‘classical physics’ and ‘the classical worldview’ had in the early twentieth century, and we should ask to what degree the term ‘classical physics’ has retrospectively coloured our image of the physics of the eighteenth and nineteenth century, by suggesting a unified and finished scheme.

Abstract 28

Klaus Volkert, University of Wuppertal

Non-Euclidean Geometries and Axiomatics

It is well known that the history of Non-Euclidean Geometry started with a question concerning axiomatics: Is it possible to deduce the postulate of parallels from the other postulates and axioms? So, from its very beginnings it was linked to axiomatics and to logic. But the progress made mainly during the 19th century was not based on improving axiomatics. Its main feature was to build up a system of Non-Euclidean Geometry on more or less the same base as used by Euclid. Only after work done by M. Pasch (1882) and mainly Italian mathematicians (Fano, Peano, Pieri, …, Houël) a satisfying axiomatization was provided by D. Hilbert (1899). Concerning Non-Euclidean Geometry this was a solution given post festum.

In my talk I will explain some aspects of this history in particular the delicate question of establishing a system of axioms and of the relations between different axioms in the system (e.g. the role of the Archimedean axiom). We will also look to the problem of finding models (in which sense?) of the axiomatic system.

Abstract 29

Paul Ziche, Utrecht University

Systems After the Systems – The Transmission and Transformation of Scientificity Between the Idealists and the Neo-Kantians

There is a standard story about the development of the relationship between philosophy and the sciences in the 19th century: After a period of (so-called ‘speculative’), all-encompassing philosophical systems in the time of German idealism, the individual sciences, in particular the natural sciences came into their right, and took over by giving more precise explanations and predictions of relevant phenomena, and by making real-world problems manageable in a scientific and technological fashion. Philosophy returned, however, in the second half of the 19th century and found a new function in critically and epistemologically reflecting upon the conditions for the success of these individual sciences. In this picture, Neo-Kantianism is one way to fill in this agenda of reclaiming lost territory for philosophy.

This paper will trace a different trajectory in the negotiations between philosophy and the sciences in the course of the 19th century. It departs from the fact that after the official demise of the idealistic systems, we do encounter a highly distinctive and broadly distributed genre of texts by authors with a strong background in the sciences who, on this basis, present comprehensive and integrative accounts of the totality of nature, including the human dimension: Typical examples are the works by Alexander von Humboldt, a book such as “Spirit and Nature” by Hans Christian Oersted, Fechner’s “Zend-Avesta”, Lotze’s “Kosmos”, works by Franciscus Donders, Carus and Schubert, and many others. Many of these texts border on the genre of popular science writings that was so important for late 19th-century monism, e.g. in the works of Ernst Haeckel, and in many cases also the radically materialist treatises of the period around 1850 fall into this category.

Being comprehensive and integrative, these texts need to develop categories for their broad projects that both draw upon recent innovations in the sciences and upon philosophical tradition, and that also open up a new readership for these projects.

This paper will look into this genre in some detail, characterize its style, and identify some of these integrative concepts. On this basis, it will be possible to discuss the transmission, and the critical discussion and transformation of an ideal such as ‘systematicity’ in this period, and, more generally, to look into changing accounts of the disciplinary positioning of philosophy vis-à-vis the sciences in a way that goes beyond the standard story.

As far as Neo-Kantian authors are concerned, there are clear traces of this genre in authors such as Lange and Cassirer; asking the questions that are sketched here will also help to bring the particular academic focus of Neo-Kantianism into sharper focus.

Abstract 30
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