Private art scholar and dealer of ancient Greek sculpture and portraits. Son of an affluent merchant in Mecklenburg, Arndt studied classical art with Johannes Overbeck in Leipzig and Enrico Brunn in Munich. His dissertation, written under Brunn, focused on Greek vase types. He never attempted a habilitationschrift. Brunn took Arndt for his assistant. Because of his financial independence, Arndt could afford to remain a private scholar.