Friedrich Albert Moritz Schlick was a German philosopher, physicist, and the founding father of logical positivism and the Vienna Circle.
Moritz Schlick around 1930
Inscription on a staircase of the main building of the University of Vienna where the murder took place.
Max Karl Ernst Ludwig Planck was a German theoretical physicist whose discovery of energy quanta won him the Nobel Prize in Physics in 1918.
Planck in 1938
Planck circa 1910
Plaque at the Humboldt University of Berlin: "Max Planck, discoverer of the elementary quantum of action h, taught in this building from 1889 to 1928."
Planck in 1918, the year he was awarded the Nobel Prize in Physics for his work on quantum theory