 Close to the same philosophical inspiration, the influential paper of Grelling and Nelson (1908) provides an attempt to unify paradoxes and to isolate their underlying structure. The philosopher Leonard Nelson was a prominent figure in the Göttingen of the early twentieth century, who had Hilbert’s strong support (see Peckhaus 1990). The paper is part of a project to develop a philosophically minded “kritische Mathematik”. It contains a new paradox (credited to Grelling) with a semantical flavor (see also the entry  self-reference):