By Patrick Roberts and Robert Spengler
The intellectual atmosphere spiraling around the Prussian summer estates of Jena, Germany, during the late eighteenth and early nineteenth centuries attracted the attention of Alexander von Humboldt. The scholarly discussions that he engaged in there shaped his career, bolstered his academic network, and providing the inspiration for the ideas that led him to found the discipline of Ecology. Today, this small city is home to one of the oldest universities in eastern Germany (Friedrich Schiller Universität) as well as a prominent cluster of three prestigious Max Planck Institutes (the Max Planck Institute for the Science of Human History, the Max Planck Institute for Biogeochemistry, and the Max Planck Institute for Chemical Ecology) that intersect the Humanities and Natural Sciences – something perhaps unprecedented for a city of its size (ca. 100,000 people). Nevertheless, most scholars, as well as much of the general public, are unaware of Jena’s scientific heritage and contributions of the many of its former residents to the development of evolutionary ecology – most prominent among them being Humboldt.
In the eighteenth century, Humboldt began visiting the city of Jena, and engaging in scholarly debates (Botting 1973; De Terra 1955; Kellner 1963; McCrory 2010). Ludwig Adrian Richter immortalized one such debate in a 1797 drawing, depicting Friedrich von Schiller, Wilhelm (his brother) and Alexander von Humboldt, and Johann Wolfgang Goethe at the famous Schiller garden house (Mommsen 2010; Wulf 2015), which still stands in Jena today (Figure 1). In particular, his meetings with the famous German novelist and scientist, Goethe, shaped the intellectual trajectory that Humboldt would later follow (Wulf 2015). Notably, many of Humboldt’s ideas, including the concept of ecological networks and the questioning of the immutability of species, spawned from these cross-disciplinary discussions with Goethe (Aulie 1960; Goethe 2009 ; McCrory 2010). Furthermore, the union of the humanities and biology led Humboldt to state that the external (including natural) world only exists in so far as it can be experienced ‘within ourselves’ (Wulf, 2015: 36). In other words, active fieldwork and experimentation are essential to the scientific endeavor.
Figure 1. Friedrich Schiller’s Gartenhaus in Jena today. Photograph taken by Robert Spengler.
Romanticizing the explorers of the Age of Discovery and building on the rapidly expanding colonial hold of European nations around the world, Humboldt undertook several amazing journeys across the tropical portions of the Americas and into the arid and mountainous regions of Central Asia (Botting 1973; Walls 2009). During his visits to South America, and notably Mount Chimborazo in Ecuador, Humboldt began to develop his Naturgemälde, a concept of the natural world as a single living organism (Rangel et al. 2014), with each community of plants being connected but also inhabiting their own niches according to altitude and local climate. In doing so, Humboldt effectively paved the way for the discipline of Ecology. Humboldt also developed the global study of Climate Science or (‘vergleichende Klimatologie’) by noting that the planetary distribution and circulation of heat was influenced by altitude, latitude, landmass, and proximity to oceans (Wulf 2015: 178).
Perhaps most amazingly, Humboldt was also the first to postulate that human alterations to the natural world could have wide-reaching consequences for human populations globally. During his visit to Lake Valencia, Venezuela, Humboldt noted “When forests are destroyed, as they are everywhere in America by the European planters… the springs are entirely dried up…” (Wulf 2015: 143-144). Certainly, Humboldt would be shaking his head at the fact that many prominent world leaders have not grasped the dramatic consequences that their policies can have on the futures of generations. Certainly, the whole basis of his founding ideas of Ecology and Climate Science is that the world operates through interconnection and that an action in one system or region will inevitably have feedbacks for other species, earth systems, and communities.
Finally, Humboldt’s contribution to the field of Evolutionary Biology should not be underestimated. His journeys into the unknown inspired many other naturalists, notably a young Charles Darwin, who claimed to take a copy of Humboldt’s Personal Narrative(1819-1829) with him on the Beagle (Darwin  1989; Keynes 2001). While many of the ideas that Humboldt first laid out are considered basic tenants of evolutionary theory today, Darwin’s concept of natural selection was dependent upon Humboldt’s observations that all species are tied into a network and one organism can influence the survival of another. Humboldt’s scholarly legacy in Jena has shaped the city’s academic landscape for two centuries. Some of the world’s greatest evolutionary theorists and taxonomists, were hosted by the city, including Friedrich Schiller, Karl Gegenbaur, Ernst Haeckel, and Matthias Schleiden, all of whom, in turn, were major promoters of Darwinian theory and shaped the biological sciences (Watts et al. 2019).
Today, in part thanks to the legacy of diverse, multidisciplinary conversations initiated by the Humboldt and Goethe, Jena hosts an impressive cluster of dedicated German research institutes, including Leibniz centres as well as the Max Planck Institutes mentioned above, and a series of leading biotechnology and optics companies seeking to put scientific principles into practice. These institutions, as well as Friedrich Schiller Universität, pride themselves on cross-disciplinary discourse (see also https://www.beutenberg.de/beutenberg-campus/institutionen/), with humanities disciplines such as Archaeology and History combining with those such as Biogeochemistry, Ecology, Chemistry, Physics, and Mathematics to initiate new collaborations, projects, insights into the relationship between humans and the natural world in the past, present, and future.
More specifically, many of the prominent topics of research being undertaken in Jena today would have held much interest for Humboldt. This is particularly the case at the Max Planck Institute for the Science of Human History (Menscheitsgeschicte). Patrick Roberts (co-author) is re-treading the steps of Humboldt by undertaking diverse, multidisciplinary fieldwork and research across the tropics (Roberts et al., 2017a,b; 2018), including the Amazon Basin and its tributaries (Caetano Andrade et al. 2019), exploring how basic human activities have permanently impacted environments that were once thought to have been pristine until the arrival of industrial capitalist forces – as well the corresponding impacts this might have had on past regional climates (Roberts et al., 2018). They have also produced of the first global book to study Tropical Forests in Prehistory, History, and Modernity (Roberts, 2019), a broad, comparative approach to the study of human relationships with these enigmatic environments that hopefully Humboldt would have appreciated.
Robert Spengler (co-author) is also tracing the footprints of Humboldt, but in this case along the routes of the ancient Silk Road, through Central Asia, an expedition he took in 1829 (Spengler 2019a). Likewise, Spengler’s research builds on Humboldt’s insights into evolutionary biology by studying plant domestication and the role that mutualistic relationships between plants and megafaunal mammals, including humans, played in shaping the evolutionary trajectories of some of the plants that dominate our kitchens today (Spengler 2019a). His research looks at what happens to certain plants when the animals that evolved to spread their seeds go extinct (Spengler 2019b). He is also interested in tracking the earliest examples of morphological change in plants as they evolved to better accommodate humans as their seed dispersal service – what we call domestication (Spengler and Mueller 2019).
Figure 2. Statue of Alexander von Humboldt outside the main building of Humboldt-Universität, Berlin. Many similar landmarks (statues, dedicated buildings, road names) can be found across Europe and the Americas highlighting the global reach of this remarkable scientist. Photograph: Christian Wolf, www.c-w-design.de Re-used without changes under the Creative Commons Attribution-Share Alike 3.0 Germany license. via wikimediacommons.org.
In sum, Jena and its researchers owe a lot to Alexander von Humboldt, while also providing him with the diverse academic space in which he could experiment with new ways of conducting science and new possibilities of thinking about the natural world. Today, parks, streets, and universities around the world are named after the person who developed Ecology, Climate Science, and Evolutionary Theory (Figure 2), though few scholars, and even fewer non-academics, know of this great intellect and the crucial role he played in the development of the natural sciences many of us learn, practice, and research today. Perhaps still fewer know the role of Jena in the career of Humboldt, and the setting it provided, and still provides, for new, cross-disciplinary approaches to the humanities and natural sciences. Yet, given the rise of scientific skepticism and political popularism it is perhaps fitting that we should remember the roles that bastions of internationalism, intellectualism, and collaboration, such as Jena and Humboldt, have played in the foundation of western science and abide by a famous saying of the latter, ‘unity in diversity’ (Wulf, 2015).
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Poster image: Stadtansicht Jena um 1900. Public Domain