Konrad Zuse and his Plankalkül: The hope to emerge from the sleep of Sleeping Beauty

Germany, 1935: the engineer Konrad Zuse (1910–1995), in the living room of his Berlin house, devotes himself to the design and construction of a binary, programmable machine, the Z1, capable of processing data in a fast and efficient way. While building his machines, he also started to devise a conceptual and notational system for writing ‘programs’ to execute applications much more complex than the basic arithmetic calculations. He delved deep into the study of formal logic in order to work out his “computation plan”, the Plankalkül. Although the Plan Calculus didn't exercise much impact on German post-World War hardships, it displays all the traits currently recognized as standard features of modern programming languages. The aim of the present study is to highlight the general purpose and technical specifics of this language, its historical and scientific background, and the philosophical inspiration leading Konrad Zuse to employ the predicate logic in the formalization of the “computation projects” for his machines.