Howard, S. (2023): Kant's late Philosophy of Nature. The Opus postumum. Cambridge: Cambridge University Press, 70 pp., ISBN 978-1-009-01376-5.

Lara Scaglia

Investigadora asociada C, IIF-UNAM

ORCID: https://orcid.org/0000-0002-7148-7456

DOI: 10.24310/nyl.19.2025.20096

Recibido: 6 de mayo de 2024

Aceptado: 6 de mayo de 2024

Stephen Howard's Kant's Late Philosophy of Nature, published in the Cambridge Elements, not only provides a clear line of interpretation of the Opus postumum, but is also didactically useful for approaching such difficult pages of Kant's philosophy. Reading these drafts is as difficult as solving a mystery: as is well known, one of the sources of problems in reading the Opus postumum is that the pages were not published chronologically. The pile of 527 manuscript pages, written between 1786 and 1803, was passed from Kant's descendants to Pastor Krause (via the Königsberg librarian Reick) and during the journey the pages were shuffled around.

Given this state of the text, many methodological questions arise: Should the Opus postumum be taken seriously? Should it be considered as a work or as a sum of drafts? Does it focus on a single problem? The pages cover topics such as: types of forces, the existence of the ether, ideas of God and the self-positioning of the thinking subject in space and time (Selbstsetzungslehre) and others. Although the number of topics is manifold, interpreters agree that Kant sets out to solve the problem of transition (Übergang), i.e. to link the a priori foundation of natural science and the specific laws of empirical physics.

However, already in the first introductory chapter, the author states his interpretative position: the Opus postumum is not intended to solve the problems left open in the critical works, but should be read as Kant's attempt to address the problem of systematizing empirical physics. Whereas in the Metaphysical Foundations Kant deals with matter in general, here he is concerned with the specific properties of matter, and whereas in the third Critique he deals with the reflective judgment and systematicity of nature, here he focuses on the systematicity of science.

In the second chapter, the author summarizes the history of the reception of Opus postumum, pointing out that around 1970, a methodological change took place. The interpreters of the early 20th century had a systematic focus: Adickes, for example, divided Kant's pages into a scientific-natural, a natural-philosophical and a metaphysical-epistemological part and recognized the novelties of Kant's thought in the realist account of things in themselves and in the doctrine of the double affection of the self (through things in themselves and appearances); while Vaihinger, who advocated a fictionalist view of things in themselves, divided the Opus postumum into two works a special natural-philosophical and a general transcendental-philosophical, and de Vleeschauwer emphasizes how Kant's view was closer to Fichte in his view of the self-position of the I.

This systematic approach changed in 1970, when Tuschling declared it impossible (because it did not take into account the relationships and differences between the stages of drafts) and advocated a historical approach, consisting of describing the development of Kant's thought and its contextualization in relation to other works. This approach paved the way for rigorous studies such as those of Förster (2000) and Edmunts (2004) but now, according to the author, it is time to rehabilitate the ambition of earlier interpreters (and later, systematic ones such as Mathieu 1989, Hoppe 1991 and Gloy 1976).

Howard opens the third chapter by recalling the standard interpretation of the 1798 letters, in which Kant claims to be tormented by an unfinished task or gap left in his system, concerning the transition from the metaphysical foundations of natural science to physics (12:257; 12;258). The actual meaning of the gap is, however, controversial: Friedman (1992), for example, sees it in the regulative and constitutive approach of the metaphysical foundation, while Edmund in the need to explain the varieties of matter. Subsequently, the author analyzes the different uses of the term ‘transition’ in Kant's works of 1781-1796 and distinguishes four: 1) simply as movement between different parts of speech; 2) as referring to different states of appearance; 3) as a reference to the principle of continuity. which regulates, for example, for instance, the transition between species; 4) in a strong and systematic sense, addressing, for example, the transition from nature to the domain of freedom.

In the drafts of the Opus postumum prior to 1799, the problem of the transition, which aims at the physical and not the supersensible, has five main characteristics. Firstly, it is not a leap, but an orderly crossing; secondly, there is a transition from one heterogeneous domain to another; thirdly, Kant describes the two domains as shores that must be joined by a bridge; and fourthly, intermediate concepts must be introduced to allow for the transition, which, fifthly, must be carried out with caution. But how are we to understand the notion of ‘gap’? Howard distinguishes between a gap as an inadequacy and as a neutral abyss, the existence of which is not a failure to be corrected, and points out that, although the doctrine tends to confuse the two, the standard interpretation regards the letters of 1798 (to Garve and Kiesewetter), in which Kant alludes to a gap in his system, as evidence that Kant became aware of a failure in his critical works and had to repair it in the drafts of the Opus postumum. But the author argues that this ‘lacuna’ does not mean that Kant failed in the critical works, but rather he realized the importance of a new step in the system, namely the transition from the metaphysics of nature to empirical physics.

In chapter 4, the author presents his view on the form and content of the transition problem: while the content of the transition is constantly changing, the form does not change and consists of the bridge provided by intermediate concepts. In agreement with Edmunts, Howard locates the starting point for embarking on the transition project in the urgency of specifying the properties of matter, with ether (or caloric) becoming the main intermediate concept from 1799. Although much attention was paid to identifying the starting point of the transition, little attention was given to the end point, i.e. physics. The author explains the lack of interest in this aspect by quoting the position of some critics, according to whom the transition to an empirical science is impossible: it is too variegated and therefore cannot be determined in advance. However, Howard adds, Kant addresses this problem and in fascicles X/XI reconsiders this view of physics as nothing more than an empirical science of experiments and observations. More specifically, Howard summarizes the numerous definitions of physics in these fascicles, emphasizing their systematic nature. However, in the drafts from 1798 to 1788, when Kant sets out to develop an elementary system, he seems to recognize that empirical natural science cannot be a system, but at best an ever-growing aggregate, because we cannot grasp a priori the results of physics. Howard argues that this theme underwent a self-critical revision in the drafts of 1799-1800, where Kant tended to define physics more widely than as a simple elementary system or a Linnean natural system, i.e. as a doctrinal system, which has as its object the elementary system and adds forms and principles to classify forces in motion. Now, unlike the critical works, Kant describes physics as the doctrine not only of external objects but also of inner ones, and this definition resembles the critical description of a physiology, i.e. a doctrine of sense objects that is fundamental to physics and psychology (cf. A845/873). Perhaps the most intriguing feature of this physiology is its subjectivity: that is, the moving forces physiology deals not only with the reaction of the object but also, and above all, the actions of the subjects. Understanding, for Kant, acts on objects and stimulates reciprocal activity.

Now the forms of movement, Kant writes, must anticipate experience in its material element. This statement has been the source of much debate among interpreters: Hoppe, for example, has pointed out that Kant proposed to anticipate matter in the proof of the ether but then abandoned this project; while Mathieu argues that he did not abandon the project and that material anticipation must be taken seriously. Howard proposes a third way: that is, both lines of interpretation fail to read the drafts as a project: Kant, in this view, is exploring both points of view on the anticipation of experience, without presenting a fully developed position. Before moving on to conclusions, the author focuses on one last topic: the system of the world, which Kant suggested in the October 1798-May 1799 drafts would constitute the second part of the transitional project. Following Edmundts' reading, Howard argues that while the elementary system proceeds synthetically (from the parts to the whole), the doctrinal follows the analytical procedure and proceeds from the idea of the whole to the parts (i.e. it contains the foundation of the elementary system, i.e. the ether as the absolute whole of matter). It then relates and compares the system of the world (according to the understanding) of these fascicles (X/XI) with the system of ideas (or reason) of the last fascicle.

This work is not only a valuable and clear support for approaching the Opus postumum, but also a clear demonstration of the relevance of these late drafts for understanding Kant's later thought, which focused on problems concerning the systematics of physics and the boundary between a priori and empirical elements of physics.

References

Edmunts, D. (2004): Kants Übergangskonzeption im Opus postumum. Zur Rolle des Nachlasswerkes für die Grundlegung der empirischen Physik. Berlin: Walter de Gruyter.

Friedman, M. (1985): Kant and the Exact Sciences. Cambridge: Harvard University Press.

Förster, E. (2000):  Kant's Final Synthesis. Cambridge: Harvard University Press

Gloy, K. (1976): Die Kantische Theorie der Naturwissenschaft. Eine Strukturanalyse ihrer Möglichkeit, ihres Umfangs und ihrer Grenzen. Berlin: de Gruyter

Hoppe, H. (1991). “Forma dat esse rei. Inwiefern heben wir in der Erkenntnis das aus der Erfahrung nur heraus, was wir zuvor in sie hineingelegt haben?” en S. Blasche, W. R. Köhler, W. Kuhlmann, P. Rohs (eds.), Übergang, Untersuchungen zum Spätwerk Immanuel Kants. Frankfurt am Main: Klostermann, pp. 49-64

Kant, I. (1990–). Gesammelte Schriften. Berlin: Brandeburgische Akademie der Wissenschaften, Walter de Gruyter

Mathieu, V. (1989). Kants Opus postumum. Ed. Held, Gerd. Frankfurt: Klostermann.

Lara Scaglia

lara.scaglia@filosoficas.unam.mx