By Isabel Jacobs

In his Helgoland, Italian physicist Carlo Rovelli evocatively describes how, in the summer of 1925, the young Werner Heisenberg came to unravel the first mysteries of quantum physics. Shortly after that summer, Heisenberg would introduce his uncertainty principle, stating that the more precisely determined the location of a particle, the less precisely can its momentum be predicted; and vice versa. Arguably the most radical paradigm shift in modern science, quantum indeterminacy was puzzling physicists and philosophers from the mid-1920s onwards. Rather than predicting what we will see, we have to accept the indeterminacy of observations, events and, subsequently—reality. But did quantum physics really mean the end of objective knowledge?

Rovelli suggests that we can make sense of a world of quanta by redefining what we mean by reality. His approach is grounded in the idea of relationality—what he calls entanglement—between observer, or subject, and the physical world. Subject and world are entangled in a “web of relations that weaves reality” (79). The idea of entanglement, popular also in contemporary feminist philosophy of science, such as works by Donna Haraway and Karen Barad, is certainly not new. In fact, post-Kantian philosophy has a lot to say about the entanglement between subject and world. It is hence no surprise that the profound problems still preoccupying physicists and philosophers of science today were already discussed a century ago; particularly by scholars in the Neo-Kantian tradition. At that time, German universities produced the avant-garde of a new scientific revolution, including Heisenberg, Albert Einstein, Hermann Weyl and David Hilbert. Their work stems from an intense dialogue with contemporaneous philosophy, particularly Husserlian phenomenology and Neo-Kantianism.

Both currents were aiming at an epistemological foundation that unified natural sciences and Geisteswissenschaften (humanities). It was precisely this interdisciplinary laboratory of ideas, traversing traditional German Idealism and modern science, that paved the way for logical positivism and analytic philosophy. In the following, I explore two early philosophical reactions to quantum indeterminismthat emerge from these Neo-Kantian circles. Certainly not claiming any interpretation of physics, I merely retrace how new concepts of reality and representation were introduced into philosophical discourse of the 1930s. My analysis aims to reveal how quantum physics offered continental thinkers an ideal starting point to explore epistemological issues. I argue that quantum indeterminism did not evoke a philosophical turn towards relativism whatsoever; on the contrary, new frameworks of representation proposed by modern physics instigated philosophers to reclaim objective knowledge.

In the 1920-30s, one of the key figures at the crossroads of Neo-Kantian idealism and philosophy of science was German philosopher Ernst Cassirer (1874-1945). An original polymath, Cassirer famously claimed that man is a symbolic rather than a rational animal. Accordingly, his universal philosophy of symbolic forms explores, among others, language, myth, religion, mathematics, and art. For Cassirer, the critical engagement with scientific revolutions such as quantum physics and Einstein’s relativity was pivotal. Particularly the problem of indeterminism puzzled Cassirer. Emigrating to Sweden after the rise of Nazism, Cassirer wrote Determinism and Indeterminism in Modern Physics in 1936. His analysis opens with Laplace’s famous demon, who knows everything at a certain moment, in a world where nothing is unknown; past, present, and future are transparent to this omniscient observer. Cassirer argues that science and metaphysics of the late 19th century were still dominated by the association of the causal principle with absolute determinism.

With the emergence of quantum physics, however, we can no longer hold onto an outdated determinism à la Laplace. Instead, a new definition of causality becomes vital. Modern physics is the ultimate death of Laplace’s demon—which, according to Cassirer, was an extinct species even before Heisenberg’s uncertainty principle. Cassirer claims that, already in classical physics, causality was a transcendental function rather than a law of nature. Only in a mythical—or pre-Kantian—worldview, causality meant that every event was predetermined by magical forces, leaving no space for human freedom. However, as Cassirer argues, such an absolutist determinism would have been alien already to most Newtonian physicists. Hence, Heisenberg’s uncertainty principle does thus not have as far-reaching metaphysical consequences as one might assume.

For Cassirer, quantum indeterminacy is thus an attack against a mythical understanding of causality rather than the death of determinism per se. It should certainly not lead us into blind relativism or nihilism. As Cassirer stresses, causality is not suspended at all; on the contrary, it remains the precondition of scientific knowledge. However, the most urgent problem of quantum physics lies in redefining reality. Like Rovelli, Cassirer interprets indeterminism through relationality. In a web of relations, causality and indeterminacy are complementary; chance itself, Cassirer argues, is not arbitrary but “strongly determined” (259). While accepting indeterminacy, modern physics still maintains a strong belief in objective reality—only the symbolization or representation of this reality changes. Cassirer calls this new mode of objective representation “quantum theoretical determinism”: a determinism that incorporates the uncertainty principle itself (266).

A few years earlier, in 1931-32, the young Russian-born French philosopher Alexandre Kojève (1902-1968)—at the time Alexander Koschewnikoff—explored the same problems. Arriving in Paris in the mid-1920s, Kojève shifted his focus from Eastern philosophy to mathematics and physics, reading major scientists from Bohr to Einstein. In 1929, Kojève wrote Zum Problem einer diskreten Welt [On the problem of a discrete world], a fascinating study on paradoxes of movement and infinity. Kojève’s unpublished text, located in the archives of the National Library in Paris, culminates in the—already Hegelian—idea that quantum physics is the first science that understands itself. In these years, Kojève visits lectures by physicists Louis de Broglie, Max Born, Enrico Fermi, Paul Langevin and Hans Kramers.

Kojève’s The idea of determinism in classical and modern physics—a title that astonishingly anticipates Cassirer’s book—was drafted in Russian in 1931 and self-translated into French the year after. It was Kojève’s second doctoral dissertation, written under the supervision of Russian philosopher Alexandre Koyré. In his subsequent seminar on Hegel’s Phenomenology, Kojève proposed an idiosyncratic interpretation of Hegel, which focused on desire, recognition and the end of history; it left a deep imprint on a whole generation of French thinkers, including Jacques Lacan, Georges Bataille, Maurice Merleau-Ponty and Jean-Paul Sartre.

Forthcoming in English translation, Kojève’s book on quantum physics, however, is today almost entirely unknown. Equally opening with Laplace’s demon, Kojève, like Cassirer, claims that quantum indeterminacy is primarily an issue of representation. The categories “determined world” and “contingent world” are not ontological but epistemological; they characterize “the way in which this being or this becoming is or can be given to a subject limited in time” (62). Scientific indeterminacy impacts the ways in which reality reveals itself to a subject. Kojève argues that there is no proof that the world of classical physics, a world of continuity, “eternal return and absolute symmetry” (98) ever corresponded to concrete reality. The idea of “a world in itself, as it exists independently of any observation, has no physical meaning” (301). Kojève emphasizes that classical physics never experimentally verified determinism; quantum physics thus only confirms the invalidity—or inapplicability—of strict determinism.

Kojève argues that “what is really new in Heisenberg’s theory, what makes it a specifically “modern” or quantum theory, is that it indicates an absolute and universal constant limit to the precision of physical observations” (178). Quantum physics’ revolutionary achievement is to specify the nature of imprecision itself. Similar to Cassirer’s “quantum theoretical determinism”, indeterminism attains a universal value in Kojève. The world of modern physics is not ruled by strict causality and yet not chaotic. While the same causes do not necessarily produce the same effects, quantum physics makes experimentally verifiable predictions (269). Reality can be viewed as if being causal.

For Kojève, this reality is even more objective than the world of classical physics. But who is the observer in a world of quanta? Kojève suggests that observing reality is not equivalent to the experience of being-in-the-world. The observer in quantum physics is the “consciousness as such (Bewusstsein überhaupt) of the German Neo-Kantians”, a “pure I” inseparable from the world it observes (190). This observer is not a unity and therefore not an individual; yet for Kojève, real experiences can only be made by individual subjects. The phenomenal experience of reality thus radically differs from scientific observation that is inherently imprecise.

Despite the striking convergences between Cassirer and Kojève, their work has not yet been read together. In fact, the affinity between the Marburg Neo-Kantian and the Russian émigré is not as unlikely as it seems. Kojève discovered Cassirer’s work during his studies in Germany in the 1920s. In Heidelberg and Berlin, Kojève studied under the influential Neo-Kantians Heinrich Rickert and Alois Riehl. In these years, reading Hermann Cohen, Kojève encounters Cassirer’s Kant’s Life and Thought. In 1932, writing his book on physics, Kojève studied Cassirer’s three-volume masterpiece The Philosophy of Symbolic Forms. It is also worth noting that Cassirer was popular among French interwar epistemologists and philosophers of science, including Gaston Bachelard, Léon Brunschvicg and Émile Meyerson. Kojève’s mentor, Koyré, admiring Cassirer’s method, was a crucial intersection between Cassirer and epistemology in exile.

We saw that epistemology after quantum physics is interested in the semiotic, or rather symbolic representation of reality. Since quantum physics does not give us an adequate image of reality, the problem of indeterminism turns into a matter of symbolization. One example of quantum physics’ symbolic access to reality is the inability to create direct images [Veranschaulichung] of what happens inside an atom. Cassirer writes: “The description [of matter] can never be regarded as a direct representation; rather, it bears a purely symbolic character. What matter really and essentially “is” cannot be expressed in any other way than in the sign language of our senses” (276). What reality really is cannot be visualized but only symbolized.

In Reality and determinism in quantum physics (1933), French-Polish epistemologist Meyerson comes to a similar conclusion. Referring to Heisenberg’s claim to “understand intuitively [anschaulich verstehen]”, Meyerson distinguishes between determination and representation (47). For Meyerson, indeterminism marks a serious crisis of image-making. The quantum physicist is confronted by two conflicting images, irreconcilable in the imagination. We cannot visualize an object that is both corpuscle and wave, and must hence be satisfied with thinking of something that is alternately one or the other. Representing reality means creating a framework that incorporates all possible forms of symbolic description—or ways of worldmaking, in Nelson Goodman’s words.

But how can we maintain strong notions of reality, truth and objectivity if our current worldview can be overcome at any time by another paradigm shift—this is, a new symbolization? Or, as Cassirer puts it in his book on indeterminism: “What is the meaning of this series of images that pass us by here in constant change and kaleidoscopic colourfulness? Is all this anything else or more than a strange phantasmagoria? What good is the abundance of images and their constant refinement if none of them has any claim to real, to final truth?” (300). For Cassirer, there is no way back to naive realism. Instead, objectivity is the constantly refined representation of reality. This continuous process of symbolizations does not mimetically represent but approximately scans [abtasten] reality, limited by the “unknowable” (277). Against pure relativism, Cassirer ambitiously claims to guarantee objectivity by synthesizing multiple systems of representation.

In his book on Einstein’s theory of relativity, Cassirer writes that an objective system encompasses all possible symbolic forms. Objective knowledge gains an “overall view of the individual views” (50). Reality as a concrete totality is the “whole of the symbolic forms” (110). While Cassirer favors this objective pluralism, Kojève tends towards ontological dualism to save objectivity as the basis of science. The key relation for Kojève is the one between observing and observed systems. While both systems interact and are thus real, they are ontologically distinct. Kojève argues that modern physics distinguishes two kinds of realism that coincided in classical physics. These two types are, in Stefanos Geroulanos’ translation, first a “metaphysical realism, which considers the physical world as a sui generis reality, […] then, the proper physical realism, which opposes, inside this world, the subject to the object both of which are real in relation to each other and situated on the same ontological plane” (99).

The whole of both systems “exists independently of both the empirical subject (the flesh and blood experience) and the knowing subject (Bewusstsein überhaupt)” (332). For Kojève, reality—not unlike Cassirer’s whole of symbolic forms—is a relational web of subject and object, observer and observed systems. There is no outside of observation; everything that can be observed exists. Hence, quantum physics does not make the world more subjective but, as the totality of interactions, objectively real. In the same vein as Cassirer’s pluralism, Kojève’s dualistic ontology of “reality-objectivity” aims to save scientific realism. As we have seen, both thinkers, not least due to their shared Neo-Kantian heritage, respond to indeterminism with an updated ontological realism.

But what else can we take from this cross-reading of Cassirer and Kojève? Ideally, it can serve as a case study of how previously disconnected texts and traditions can mutually enrich or distort each other. The goal of such a juxtaposition is not only to renew our perception of a particular author’s work; it also aims at creating a more complex picture of twentieth-century intellectual history with regards to transnational networks, migration, and the transfer of ideas. Massimo Ferrari recently argued that Cassirer’s significance for the development of post-war philosophy of science—and the impact of German Neo-Kantianism more broadly—is yet to be discovered. The Parisian émigré circles around Kojève and Koyré might be precisely this productive missing link between German Neo-Kantianism and philosophy of science in the 1960s, both in Europe and the US.

Isabel Jacobs is a doctoral candidate in Comparative Literature at Queen Mary University of London. Her current research explores the work of Alexandre Kojève from a transnational perspective. Her interests include Soviet and Russian émigré philosophy, German-Jewish thought, global intellectual history, cinema, and aesthetics. She received her M.A. in Russian and East European Literature and Culture from UCL SSEES and her B.A. in Philosophy and Slavic Studies from Heidelberg University. 

Featured Image: Pavel Filonov, Countenances (Faces on an Icon), 1940; Public Domain in the United States.