"The profound purely scientific significance of Riemann's work in pure mathematics and mathematical physics has been long since recognised, and time is more and more disclosing the great philosophical import of portions of that same work, as for example, of the famous Habilitationschrift on "The Hypotheses that Form the Foundations of Geometry." Riemann was indeed distinctly a philosophical mathematician. Grundlage (the foundations of things), more than anything else, fascinated his marvellous genius, and his greatest work was exploration among the roots of knowledge... Some of his profoundest ideas have certainly not been duly exploited. In their German dress, they are to many people practically inaccessible. ... Like Riemann's purely philosophical ideas, which were influenced by Fechner, his psychology will, at least in its terminology, be found to be at variance in many points with the views and tendencies of the time. They have, however, a quite independent significance as throwing light upon Riemann's own intellectual development, and thus, apart from whatever intrinsic merit they may possess, form a valuable page in the history of the development of thought."