Paul Carus (German: [ˈkaːʀʊs]; 18 July 1852 – 11 February 1919) was a German-American author, editor, a student of comparative religion and philosopher.
Carus was born in Ilsenburg, Germany, and educated at the universities of Strassburg (then Germany, now France) and Tübingen, Germany. After obtaining his PhD from Tübingen in 1876 he served in the army and then taught school. He had been raised in a pious and orthodox Protestant home, but gradually moved away from this tradition.
He left Bismarck's Imperial Germany for the United States, "because of his liberal views". After he immigrated to the USA (in 1884) he lived in Chicago, and in LaSalle, Illinois. Paul Carus married Edward C. Hegeler's daughter Mary (Marie) and the couple later moved into the Hegeler Carus Mansion, built by her father. They had six children.
In the United States, Carus briefly edited a German-language journal and wrote several articles for the Index, the Free Religious Association organ.
Soon after, he became the first managing editor of the Open Court Publishing Company, founded in 1887 by his father-in-law. The goals of Open Court were to provide a forum for the discussion of philosophy, science, and religion, and to make philosophical classics widely available by making them affordable.
He also acted as the editor for two periodicals published by the company, The Open Court and The Monist.
He was introduced to Charles Sanders Peirce, the founder of American Pragmatism, by Judge Francis C. Russell of Chicago. Carus stayed abreast of Peirce's work and would eventually publish a number of his articles.