This paper investigates different research traditions in early German-speaking theoretical biology. A century after the term ‘biology’ was coined, a number of scholars started to argue for the need to develop a ‘theoretical biology’. While through the works of, among others, Johannes Reinke and Jacob von Uexküll interests in biological theorizing grew steadily, the new field’s aims and research methods were quite diverse. Theoretical biology was argued to allow conceptual clarification, theoretical ordering, organization of research activities, better communication of results, abstracting from the ‘burden of details’, securing the autonomy of biology from physics, and ultimately, unifying biological research. Due to this heterogeneity still today large part of early theoretical biology remains poorly understood. By focusing on two of the most central figures in this young discipline, Julius Schaxel and Adolf Meyer-Abich, this paper, first, seeks to disentangle and classify individual motivations of scholars to promote theorizing in biology. This includes clarifying theorists’ (i) different views on the relationship between theory and experimental practice in biology, (ii) underlying philosophical frameworks (e.g., holism, dialectical materialism), and (iii) terminological characterizations of the new field (e.g., ‘general biology’ vs. ‘theoretical biology’). Second, the paper provides an overview of the structure and conceptual debates of this large (and today largely forgotten) German-speaking theoretical research community until the end of WWII. Therefore, contributions to the two central book series of the time, Schaxel’s ‘Abhandlungen zur theoretischen Biologie’ and Meyer-Abich’s ‘Bios’ will be discussed.

The concept for which Uexküll is best known is his notion of the environment (Umwelt) as a species-specific subjective construction. This concept, however, takes its full meaning when situated in the context of Uexküll’s overall reflection on biology. The constitution of the perceptive and operative Umwelt is seen by Uexküll as part of a wider complex of organized morphogenetic, physiological, anatomical, and behavioural processes. This clearly emerges from the two editions of Uexküll’s Theoretische Biologie (1920; second, expanded edition 1928). Starting from these considerations, this paper aims to provide an overview of the links between Uexküll’s theoretical biology and related scholars and debates. The discussion will center on two chief issues. Firstly, the influence of other authors (Johannes Müller, Hermann von Helmholtz, Jacques Loeb) on Uexküll will be outlined. This will give us the opportunity to discuss Uexküll’s reception of Immanuel Kant’s transcendental approach; through the mediation of Helmholtz, in fact, Kant’s theory of perception assumes a great relevance for Uexküll’s physiology and theoretical biology (not by chance, the first two chapters of Theoretische Biologie are titled respectively "space" and "time). Secondly, the paper addresses Uexküll’s position in some long-term biological debates in the 19th and early 20th Centuries: the mechanist-vitalist debate; the discussion about nature and function of cellular protoplasm; the issue of teleology (in Uexküll’s terminology, Zweckmässigkeit, “purposefulness”) in biological phenomena. A final evaluation will be offered on the possibility of updating Uexküll’s theoretical biology.

In the summer of 1929, Raymond Pearl, editor of the Quarterly Review in Biology, responded to English biologist J. H. Woodger with a warning. Woodger had submitted a lengthy, sophisticated essay on theoretical biology to the QRB. Though he recognized it as an important contribution, Pearl thought it would not fly with the journal’s editorial board. “Most working biologists, at any rate in America,” cautioned Pearl, “do not like to think and look with a very fishy eye on anything which savors of philosophy.” This essay begins with Raymond Pearl’s claim. Was it true that theoretical biology foundered in the interwar period in the United States? If so, why? And how unique was the US? Woodger collaborated with Continental biologists but found the inspiration for his own theoretical biology amidst English philosophers Bertrand Russell and Alfred North Whitehead. So, did biologists in the United Kingdom fare any better in fostering theoretical biology than in the US? In order to answer these questions, this essay will weigh claims by historians of the life sciences that, “ideas of science come second in every sense, to the work of science” (Endersby 2007) against the methodological and sociological trends in Anglo-American biology in the mid-twentieth century.

Over the course of the twentieth century, theoretical biology changed beyond all recognition. Although the field today is synonymous with mathematical biology, when it first emerged it had a drastically different agenda: to critically analyze the conceptual foundations of biology in order to resolve longstanding theoretical disputes and bring about the epistemic unification of biological science. The field began acquiring its now familiar mathematical character in the 1930s and 40s, as formal models became increasingly applied in different areas in biology, such as ecology and evolution. With the rise of molecular biology in the 1950s and 60s the non-formal, philosophical approach to theoretical biology that had been dominant in earlier decades came to be perceived as old-fashioned and irrelevant, if not downright pernicious. Nevertheless, a few authors attempted to rehabilitate this older tradition, arguing for the necessity of philosophical reflection about the theoretical basis of biology. This paper explores these efforts and tries to understand why they ultimately failed to convince the broader biological community about the importance of ‘doing theory’. It discusses the neglected work of Walter Elsasser, Arthur Koestler’s Albach symposium on the limits of reductionism, Conrad Waddington’s Serbelloni meetings that led to the publication of the four-volume series called Towards a Theoretical Biology, and Brian Goodwin’s challenge of the Neo-Darwinian paradigm and his unsuccessful promotion of ‘process structuralism’. Although these developments have been mostly forgotten, they are crucial for understanding how views regarding the role of theory in biology have changed in the last hundred years.