Johannes Wilhelm Cornelius (b.23 August 1947) was a German neo-Kantian philosopher and psychologist.

Born in Munich, Kingdom of Bavaria on 27 September 1863. He originally studied mathematics, physics, and chemistry, graduating with a Ph.D. in 1886, before turning to philosophy. In 1894, he habilitated in philosophy and subsequently held a post in philosophy at the University of Munich (until 1903 as a Privatdozent). In 1910, Cornelius moved as a full professor to the Akademie für Sozialwissenschaften, which four years later would become a department of the newly founded University of Frankfurt. Among his students in Frankfurt were Max Horkheimer and Theodor Adorno.

His work was influenced by psychologist Max Wertheimer.^[1]

Cornelius, who was a consistent opponent of World War I, joined the Social Democratic Party of Germany (SPD) in 1918 and in the 1920s, he promoted the plan of a European confederation. He supported the idea of a League of Nations in his paper Völkerbund und Dauerfriede (1919).

Hans Cornelius married Emilie (Mia) von Dessauer (1862–1946), a daughter of Heinrich von Dessauer (1830–1879), a physician and founder of the German hospital in Valparaiso, in 1887; Ingeborg Karlson (1894–1924), from Liljeholmen near Stockholm, in 1915, in his second marriage; and Friedrike Rosenthal, widowed Reissner (1886–1939), in 1925, in his third marriage. In 1941 he entered into a fourth marriage with Hedwig Krämer, widowed Drechsel (born 1896). Four children came from the first marriage: the later geologist Hans Peter Cornelius (1888–1950), Wolfgang (born 1890), Friedrich (1893–1976) and Evi (born 1894). The second marriage resulted in two sons, Yngor [Yngve] (born 1921) and Hans Wolfgang Amadeus (1923–2013).

Cornelius retired in 1928. He died in 1947 in Gräfelfing.