Ernst Marcus

Ernst Marcus: The Judge Who Tried to Refute Einstein

He spent his working days on the bench in Essen, a Ruhr city of coal and steel, deciding ordinary cases. In the evenings he built a system. From 1899 the philosopher Salomo Friedlaender began meeting him regularly and came away convinced he had found the most rigorous mind in Germany — he called Ernst Marcus "the Krupp of logic," naming him after the armaments dynasty whose works dominated the town. Marcus used that logic, in the last years of his life, to argue that Albert Einstein was wrong.

Kamen to the Bench

Marcus was born on 3 September 1856 in Kamen, in Westphalia, to Robert Ruben Marcus and his wife Berta, a Jewish family of the industrialising Ruhr. He studied law at Bonn and Berlin, qualified as an Assessor in 1889, and in 1890 was appointed a judge in Essen. In 1893 he married Berta Auerbach; they had three children. His papers are held today by the Leo Baeck Institute in New York, the archive of German-Jewish life.

Nothing in that career suggests what followed. Marcus held no academic post and belonged to no philosophical faculty. His philosophical interests developed after he had already entered legal practice, and every book he wrote was written alongside a full judicial workload.

Defending the Thing-in-Itself

Marcus was a Kantian in a period when being a Kantian meant choosing sides. Kant's philosophy had been reopened by rival schools, each claiming to have found what he really meant, and Marcus set himself against the two most prominent revisionists of his day: Hermann Cohen and Leonard Nelson. Where their new interpretations sought to dispose of Kant's most awkward doctrine, Marcus insisted on keeping it.

That doctrine is the thing-in-itself: Kant's claim that behind the world as it appears to us there stands reality as it is in itself, which we cannot experience. Most of Kant's readers had found this either incoherent or dispensable. Marcus argued that the thing-in-itself remained central to the whole system and, more provocatively, that it was deducible from reason rather than merely posited. Alongside this he developed a theory of an a priori "organism" — a structured apparatus which the "I" constructs, through which experience becomes possible at all.

The books came steadily. *Kants Revolutionsprinzip* appeared in 1902, arguing for the revolutionary character of Kant's central move. *Das Erkenntnisproblem* — the problem of knowledge — followed in 1905. *Die Beweisführung in der Kritik der reinen Vernunft* (1914) worked through the structure of proof in the *Critique of Pure Reason* itself. *Kants Weltgebäude*, on Kant's construction of the world, appeared in 1917, and the strange *Theorie einer natürlichen Magie* in 1924. Eight works in all were published between 1902 and 1927.

The Aether and the Attack on Relativity

Marcus's boldest project drew on Kant's *Opus Postumum*, the tangle of unfinished manuscripts the philosopher left at his death, in which Kant had worked on a theory of the aether — a universal medium filling space. The standard scholarly edition and interpretation of these papers was the work of Erich Adickes, and Marcus disagreed with him sharply, developing his own aether theory out of the same material.

He then turned it against modern physics. Einstein's special relativity had made the aether unnecessary and had made space and time relative to the observer — which, if true, appeared to demolish Kant's account of space and time as the a priori forms of all intuition. Marcus refused the conclusion. In *Kritik des Aufbaus der speziellen Relativitätstheorie* (1926) he attacked the construction of the theory itself, and in *Die Zeit- und Raumlehre Kants* (1927) he restated Kant's doctrine of space and time against it. He died in Essen on 30 October 1928, a little over a year after the last of these appeared.

Friedlaender

The one relationship that carried Marcus's work outward was with Salomo Friedlaender, who from 1899 met him regularly and became his most devoted expositor. Friedlaender admired his theses without reservation, produced secondary works examining Marcus's philosophy and his campaign against Einstein, and was in turn decisively shaped by him. Marcus is described as a major influence on Friedlaender's thought — which means that his ideas reached a wider literary and philosophical public largely through a single disciple's advocacy.

Why Ernst Is Called a Genius

The quality claimed for Marcus is austere and technical: the ability to hold a philosophical system's least popular commitment and derive it rather than abandon it. Everyone in his generation could see that Kant's thing-in-itself was an embarrassment; Cohen and Nelson each proposed ways around it. Marcus went the other way and argued it was deducible from reason itself — an extraordinarily demanding position to defend, and he defended it across eight books, in his spare time, from a judge's chambers, with no colleagues, no students and no faculty. Friedlaender's phrase, the Krupp of logic, was meant precisely: what struck those who met him was the sheer forging-strength of the reasoning. His willingness to reconstruct a theory from Kant's unfinished *Opus Postumum* and then set it against the most celebrated physics of the century shows a mind entirely unimpressed by consensus.

The counter-case is straightforward. He was wrong about the thing that made him most conspicuous. The critique of special relativity failed; the aether he defended does not exist; and a philosopher who tries to refute a physical theory on transcendental grounds in 1926 is, however rigorous, arguing from the wrong side of a settled question. His broader project — rescuing the thing-in-itself by deduction — persuaded almost no one, and neo-Kantianism developed along the lines Cohen and Nelson drew rather than his. He founded no school; his reception ran through essentially one admirer. *Theorie einer natürlichen Magie* is not the title of a book that a discipline takes to its heart. What survives is not a body of accepted results but the spectacle of an unusually powerful intellect working alone and, in the end, defending a position the century had already left behind.

Legacy

Marcus is remembered today chiefly through two channels: the archive of his papers at the Leo Baeck Institute, and Friedlaender's writings, in which his ideas were absorbed and transmitted to readers who never opened one of his own books. Historians of neo-Kantianism cite him as the most determined defender of the thing-in-itself in a period when that made him nearly alone, and historians of the reception of relativity list him among the philosophers who tried, on Kantian grounds, to hold the line against Einstein and lost. He is a case study in a real and uncomfortable fact about intellectual life: that rigour and independence, in generous supply, are no protection against backing the wrong argument.