Rupert Riedl’s Path of Cognition

In 1944, at the age of 19, Rupert Riedl drafted a plan of the fields of research he intended to address during his future career. The sketch, still in existence today, included hydrobiology, morphology, evolution, theoretical biology, and cultural issues. He then proceeded to implement this plan and became one of Austria’s most influential biologists following WWII. This astonishing feat was based on an understanding of science as adventure and discovery, akin to the arts, that he had derived from adolescent readings of Jules Verne, Humboldt, and Goethe. In defending the holistic reasoning initiated by these early influences he later positioned himself frequently in contrast to the analytical and technology-driven biosciences, in a lifelong rebellion against what he characterized as reductionist and mainstream positions. Uncompromising in every regard, he was able to make genuine and lasting contributions to all the fields he had targeted. Rupert Riedl’s death in September of last year marked the end of a highly successful career as a Humboldtian explorer into multiple fields of biology, from underwater caves and sandy marches to jaw worms and human minds. Owing him a lot, I would like to sketch the most important feats of his “path of cognition,” a term he used for the acquisition of knowledge, especially in scientific discovery. Discovery was to be done at sea, preferably on board of ships that glide over deep-blue waters with elegantly curved sails. In the absence of ships, Riedl’s path took its course in the late 1940s with extensive field trips to the Mediterranean, which, still a student of zoology, he loved to call expeditions. Without any prior training in marine biology, in fact without ever having been to the sea at all, Riedl and his companions set their minds on the uncharted realms of submarine worlds. This was as much a conscious choice of scientifically untrodden (sub)terrain as it was a romantic rebellion against the limited possibilities of a marine biology based on material obtained by fishing and dredging. Using self-tailored diving gear and research equipment, the intrepid explorers of submerged habitats were able to collect new information, specimens, and rare film material, resulting in a large number of publications and eventually a field guide to the Adriatic Sea (1963). Despite being shooed away early on from the most highly reputed European marine biology institution of the time, the Stazione Zoologica di Napoli, Riedl became an internationally renowned marine biologist, equally contributing to marine ecology and to the systematics of marine organisms. Major achievements were his publications on marine caves (1966), sandy sea bottoms (Fenchel and Riedl 1970), and the dynamics of shore water movement (1971; Riedl et al. 1972). Soon Riedl’s attention turned to the exotic organisms living in these habitats, in particular to the fauna of the largely unknown phylum of gnathostomulida and their adaptations to highly specialized environments (e.g., 1969, 1970). The strong morphological tradition of the Zoology Institute at the University of Vienna, where he became an assistant professor in 1953, prompted him to study the detailed anatomy of these organisms. Attempts at classification soon found him pondering classical issues of morphology: bauplans, homology, homoplasy, and the principles of anatomical organization. The pervasive problems associated with the taxonomic use of morphological characters led him to consider the conditions of their evolutionary origins, and during his period as Kenan Professor of Zoology and Marine Sciences at the University of North Carolina, Chapel Hill (1968–1971), he worked out a detailed theory of morphological evolution. Again assuming a stance of rebellion against a dominant view, the sole importance of population genetics in neo-Darwinism, he used an idiosyncratic terminology that led many to disregard the resulting major volume, Order in Living Organisms, first published in German (1975), although the English translation (1978) by the paleontologist Richard Jefferies made it more palatable. This volume, his most seminal publication, summarized the key problems of phenotypic organization in organismal evolution and proposed a systems-theoretical extension to the neo-Darwinian