Gustav Ratzenhofer (July 4, 1842 in Vienna – October 8, 1904 in the Atlantic Ocean) was an Austrian military officer, philosopher and sociologist.
Ratzenhofer was a watchmaker and joined in 1859 by the master watchmaker examination in the Austrian army, in which he made a brilliant career: second lieutenant (1864), member of the General Staff (1872), director of the Army Archives (1878), finally as Feldmarschall - lieutenant president of the Military High Court (1898).
In 1901 Ratzenhofer left the army and devoted himself entirely to his private study of philosophy and sociology, where he was strongly influenced by active contacts with Ludwig Gumplowicz.
Ratzenhofer understood sociology based on Herbert Spencer, Charles Darwin and Auguste Comte as part of a comprehensive philosophy, which he described as "positive monism".
Ratzenhofer tried to explain all the laws of human coexistence by scientific methods, and emphasized the unity of Weltgesetzlichkeit.