In the artist's words:

Wilhelm Vossenkuhl is a German philosopher and professor emeritus of philosophy at the Ludwig Maximilian University of Munich. He is the author and editor of several publications, including popular science works such as Philosophie für die Westentasche. In the academic field, Vossenkuhl has made a name for himself primarily through his work on Wilhelm von Ockham and Ludwig Wittgenstein, the theory of action and ethics.

https://de.wikipedia.org/wiki/Wilhelm_Vossenkuhl