He was offered professorships by many of the most prestigious of the American universities but, after careful consideration, he decided to remain loyal to Zurich.
Siya ay inaalok professorships sa pamamagitan ng marami sa mga pinaka-prestihiyoso ng American unibersidad ngunit, matapos ang maingat na pagsasaalang-alang, siya ay nagpasya na manatiling tapat sa Zurich.