The year 2025 marks the centenary of Rupert Riedl, the founding president of the Konrad Lorenz Institute for Evolution and Cognition Research (KLI), which itself was established 35 years ago in 1990. Since its inception, the KLI has played a pivotal role in supporting research in theoretical biology. To commemorate this milestone, the KLI hosted a day-long symposium on 16 June 2025, under the theme "What is Theoretical Biology?"

The event commenced with a welcome address by KLI President Philipp Mitteroecker, followed by a keynote lecture from Honorary President Gerd Müller titled "Rupert Riedl and the Austrian School of Theoretical Biology." Prof. Müller’s talk provided historical context for the academic environment in which Riedl developed his interest in theoretical biology and introduced key concepts of his theoretical approach to evolution.

The symposium featured several distinguished speakers who explored different dimensions of theoretical biology. Manfred Laubichler (Arizona State University, USA) spoke about "The International Context of Theoretical Biology," while Mihaela Pavli?ev (University of Vienna) discussed "The Role of Riedl’s Systems Theory in Contemporary Evolutionary Biology." Philipp Mitteroecker (KLI and University of Vienna) spoke about "Theoretical Biology and Morphometrics: On the Generation and Canalization of Morphological Variation During Development." Laura Nuño de la Rosa (Complutense University of Madrid) addressed "The Evolvability of Riedl’s Ideas," and Kalevi Kull (University of Tartu, Estonia) concluded the series with a presentation titled "Towards Semiotics in Theoretical Biology."

The presentations were followed by a panel discussion on "The Future of Theoretical Biology," moderated by Barbara Fischer (Group Leader, Evolutionary Biology, KLI). The panel included Gregory Radick (University of Leeds), Eörs Szathmáry (Eötvös Loránd University), and Günter Wagner (Yale University; University of Vienna).

The symposium was attended by a wide audience, including prominent academics from Austria and abroad, as well as students, fellows, and participants of the upcoming workshop on Conrad Waddington. The day concluded with a splendid dinner reception.