Zurich. A young (only 19 years old) John von Neumann began his PhD at ETH Zurich. According to his friend Theodore von Kármán, von Neumann’s father wanted John to pursue industry and thus invest his time in a more financially worthwhile endeavor than mathematics. Indeed, his father asked von Kármán to persuade his son not to pursue mathematics as his major. Von Neumann and his father decided that the best career path was to become a chemical engineer. This wasn’t something von Neumann had much knowledge of, so he was assigned a two-year undergraduate chemistry course at the University of Berlin (TU Berlin), after which he took the entrance exam to the prestigious ETH Zurich, which he passed in September 1923. At the same time, von Neumann also entered Pázmány Péter University in Budapest as a PhD candidate in mathematics. For his thesis, he chose to produce an axiomatization of Cantor’s set theory. He graduated as a chemical engineer from ETH Zurich in 1926 and passed the final examinations (at just 22 years old) for his PhD in mathematics simultaneously with his master’s degree in chemical engineering, of which Wigner wrote: “A doctoral thesis and an examination evidently did not constitute a worthwhile effort.” He then went to Göttingen to study mathematics under David Hilbert.
