Abraham A. Fraenkel in Tablet:
My report about this last phase of my life in Germany should not close without my describing some people who in every respect deserve to be highlighted. Those who first come to mind are eight scientists. Of course, I cannot and do not wish to offer biographies or acknowledgments of their scientific accomplishments that can be easily found elsewhere. Instead, I will mention primarily those aspects that were significant for my own development. Of these eight men, there are four mathematicians: Hilbert, Brouwer, Landau, and von Neumann; two physicists: Einstein and Niels Bohr; and two Protestant theologians and philosophers: Rudolf Otto and Heinrich Scholz.
In his time David Hilbert (1862–1943) was the most significant mathematician in the world. For a long time, he shared this honor with Henri Poincaré, who died in 1912. In contrast to most of his colleagues, Hilbert’s discoveries in successive periods encompassed the broadest range of pure mathematics. He hardly dealt with applied mathematics, except for one not very successful period devoted to physics. He was born in Königsberg and never relinquished his East Prussian accent. The number of true anecdotes about him is legion, as he was, without doubt, a highly original character. He became a professor in Göttingen in 1895 and declined appointments to Leipzig, Berlin, Heidelberg, and in 1919 to Bern. He was correctly considered the scientific head of German mathematics, and was acknowledged throughout the world. Students flocked to him from all over Europe and the United States. At the second International Congress of Mathematicians in Paris in 1900 he gave a programmatic lecture on “Mathematical Problems.” The 23 key unsolved problems he enumerated largely determined the developments in mathematics in the subsequent decades. Most of these problems have since been solved, problem No. 1 by Paul J. Cohen in 1963.